Publications

Abstract

This study aimed first to determine whether there is a delay associated with processing words in an unfamiliar regional accent compared to words in a familiar regional accent, and second to establish whether short-term exposure to an unfamiliar accent affects the speed and accuracy of comprehension of words spoken in that accent. Listeners performed an animacy decision task for words spoken in their own and in an unfamiliar accent. Next, they were exposed to approximately 20 minutes of speech in one of these two accents. After exposure, they repeated the animacy decision task. Results showed a considerable delay in word processing for the unfamiliar accent, but no effect of short-term exposure.

Abstract

We present the Retention and Recognition model (R&R), a probabilistic exemplar model that accounts for segmentation in Artificial Language Learning experiments. We show that R&R provides an excellent fit to human responses in three segmentation experiments with adults (Frank et al., 2010), outperforming existing models. Additionally, we analyze the results of the simulations and propose alternative explanations for the experimental findings.

Abstract

The present paper assesses discourse-pragmatic factors as a potential explanation for the subject-object assymetry in early child language. It identifies a set of factors which characterize typical situations of informativeness (Greenfield & Smith, 1976), and uses these factors to identify informative arguments in data from four children aged 2;0 through 3;6 learning Inuktitut as a first language. In addition, it assesses the extent of the links between features of informativeness on one hand and lexical vs. null and subject vs. object arguments on the other. Results suggest that a pragmatics account of the subject-object asymmetry can be upheld to a greater extent than previous research indicates, and that several of the factors characterizing informativeness are good indicators of those arguments which tend to be omitted in early child language.

Abstract

This special issue is devoted to a relatively neglected topic in linguistics, namely the verbal component of locative statements. English tends, of course, to use a simple copula in utterances like “The cup is on the table”, but many languages, perhaps as many as half of the world's languages, have a set of alternate verbs, or alternate verbal affixes, which contrast in this slot. Often these are classificatory verbs of ‘sitting’, ‘standing’ and ‘lying’. For this reason, perhaps, Aristotle listed position among his basic (“noncomposite”) categories.

Abstract

Most work on part-of-speech (POS) tagging is focused on high resource languages, or examines low-resource and active learning settings through simulated studies. We evaluate POS tagging techniques on an actual endangered language, Griko. We present a resource that contains 114 narratives in Griko, along with sentence-level translations in Italian, and provides gold annotations for the test set. Based on a previously collected small corpus, we investigate several traditional methods, as well as methods that take advantage of monolingual data or project cross-lingual POS tags. We show that the combination of a semi-supervised method with cross-lingual transfer is more appropriate for this extremely challenging setting, with the best tagger achieving an accuracy of 72.9%. With an applied active learning scheme, which we use to collect sentence-level annotations over the test set, we achieve improvements of more than 21 percentage points

Abstract

We present results from an experiment which shows that voice perception is influenced by the phonetic content of speech. Dutch listeners were presented with thirteen speakers pronouncing CVC words with systematically varying segmental content, and they had to discriminate the speakers’ voices. Results show that certain segments help listeners discriminate voices more than other segments do. Voice information can be extracted from every segmental position of a monosyllabic word and is processed rapidly. We also show that although relative discriminability within a closed set of voices appears to be a stable property of a voice, it is also influenced by segmental cues – that is, perceived uniqueness of a voice depends on what that voice says.

Abstract

The use of subject pronouns by bilingual speakers using both a pro-drop and a non-pro-drop language (e.g. Spanish heritage speakers in the USA) is a well-studied topic in research on cross-linguistic influence in language contact situations. Previous studies looking at bilinguals with different proficiency levels have yielded conflicting results on whether there is transfer from the non-pro-drop patterns to the pro-drop language. Additionally, previous research has focused on speech patterns only. In this paper, we study the two modalities of language, speech and gesture, and ask whether and how they reveal cross-linguistic influence on the use of subject pronouns in discourse. We focus on elicited narratives from heritage speakers of Turkish in the Netherlands, in both Turkish (pro-drop) and Dutch (non-pro-drop), as well as from monolingual control groups. The use of pronouns was not very common in monolingual Turkish narratives and was constrained by the pragmatic contexts, unlike in Dutch. Furthermore, Turkish pronouns were more likely to be accompanied by localized gestures than Dutch pronouns, presumably because pronouns in Turkish are pragmatically marked forms. We did not find any cross-linguistic influence in bilingual speech or gesture patterns, in line with studies (speech only) of highly proficient bilinguals. We therefore suggest that speech and gesture parallel each other not only in monolingual but also in bilingual production. Highly proficient heritage speakers who have been exposed to diverse linguistic and gestural patterns of each language from early on maintain monolingual patterns of pragmatic constraints on the use of pronouns multimodally.

Abstract

Recent work has made available a number of standardized meta- analyses bearing on various aspects of infant language processing. We utilize data from two such meta-analyses (discrimination of vowel contrasts and word segmentation, i.e., recognition of word forms extracted from running speech) to assess whether the published body of empirical evidence supports a bottom-up versus a top-down theory of early phonological development by leveling the power of results from thousands of infants. We predicted that if infants can rely purely on auditory experience to develop their phonological categories, then vowel discrimination and word segmentation should develop in parallel, with the latter being potentially lagged compared to the former. However, if infants crucially rely on word form information to build their phonological categories, then development at the word level must precede the acquisition of native sound categories. Our results do not support the latter prediction. We discuss potential implications and limitations, most saliently that word forms are only one top-down level proposed to affect phonological development, with other proposals suggesting that top-down pressures emerge from lexical (i.e., word-meaning pairs) development. This investigation also highlights general procedures by which standardized meta-analyses may be reused to answer theoretical questions spanning across phenomena.

Abstract

Theories of language acquisition and perceptual learning increasingly rely on statistical learning mechanisms. The current meta-analysis aims to clarify the robustness of this capacity in infancy within the word segmentation literature. Our analysis reveals a significant, small effect size for conceptual replications of Saffran, Aslin, & Newport (1996), and a nonsignificant effect across all studies that incorporate transitional probabilities to segment words. In both conceptual replications and the broader literature, however, statistical learning is moderated by whether stimuli are naturally produced or synthesized. These findings invite deeper questions about the complex factors that influence statistical learning, and the role of statistical learning in language acquisition.

Abstract

In Yukatek Maya, event types are lexicalized in verb roots and stems that fall into a number of different form classes on the basis of (a) patterns of aspect-mood marking and (b) priviledges of undergoing valence-changing operations. Of particular interest are the intransitive classes in the light of Perlmutter’s (1978) Unaccusativity hypothesis. In the spirit of Levin & Rappaport Hovav (1995) [L&RH], Van Valin (1990), Zaenen (1993), and others, this paper investigates whether (and to what extent) the association between formal predicate classes and event types is determined by argument structure features such as ‘agentivity’ and ‘control’ or features of lexical aspect such as ‘telicity’ and ‘durativity’. It is shown that mismatches between agentivity/control and telicity/durativity are even more extensive in Yukatek than they are in English (Abusch 1985; L&RH, Van Valin & LaPolla 1997), providing new evidence against Dowty’s (1979) reconstruction of Vendler’s (1967) ‘time schemata of verbs’ in terms of argument structure configurations. Moreover, contrary to what has been claimed in earlier studies of Yukatek (Krämer & Wunderlich 1999, Lucy 1994), neither agentivity/control nor telicity/durativity turn out to be good predictors of verb class membership. Instead, the patterns of aspect-mood marking prove to be sensitive only to the presence or absense of state change, in a way that supports the unified analysis of all verbs of gradual change proposed by Kennedy & Levin (2001). The presence or absence of ‘internal causation’ (L&RH) may motivate the semantic interpretation of transitivization operations. An explicit semantics for the valence-changing operations is proposed, based on Parsons’s (1990) Neo-Davidsonian approach.

Abstract

Brain oscillations have been shown to track the slow amplitude fluctuations in speech during comprehension. Moreover, there is evidence that these stimulus-induced cortical rhythms may persist even after the driving stimulus has ceased. However, how exactly this neural entrainment shapes speech perception remains debated. This behavioral study investigated whether and how the frequency and phase of an entrained rhythm would influence the temporal sampling of subsequent speech. In two behavioral experiments, participants were presented with slow and fast isochronous tone sequences, followed by Dutch target words ambiguous between as /ɑs/ “ash” (with a short vowel) and aas /a:s/ “bait” (with a long vowel). Target words were presented at various phases of the entrained rhythm. Both experiments revealed effects of the frequency of the tone sequence on target word perception: fast sequences biased listeners to more long /a:s/ responses. However, no evidence for phase effects could be discerned. These findings show that an entrained rhythm’s frequency, but not phase, influences the temporal sampling of subsequent speech. These outcomes are compatible with theories suggesting that sensory timing is evaluated relative to entrained frequency. Furthermore, they suggest that phase tracking of (syllabic) rhythms by theta oscillations plays a limited role in speech parsing.

Abstract

Speech is an acoustic signal with inherent amplitude modulations in the 1-9 Hz range. Recent models of speech perception propose that this rhythmic nature of speech is central to speech recognition. Moreover, rhythmic amplitude modulations have been shown to have beneficial effects on language processing and the subjective impression listeners have of the speaker. This study investigated the role of amplitude modulations in the political arena by comparing the speech produced by Hillary Clinton and Donald Trump in the three presidential debates of 2016. Inspection of the modulation spectra, revealing the spectral content of the two speakers’ amplitude envelopes after matching for overall intensity, showed considerably greater power in Clinton’s modulation spectra (compared to Trump’s) across the three debates, particularly in the 1-9 Hz range. The findings suggest that Clinton’s speech had a more pronounced temporal envelope with rhythmic amplitude modulations below 9 Hz, with a preference for modulations around 3 Hz. This may be taken as evidence for a more structured temporal organization of syllables in Clinton’s speech, potentially due to more frequent use of preplanned utterances. Outcomes are interpreted in light of the potential beneficial effects of a rhythmic temporal envelope on intelligibility and speaker perception.

Abstract

Learning a language involves learning how to map specific forms onto their associated meanings. Such mappings can utilise arbitrariness and non-arbitrariness, yet, our understanding of how these two systems operate at different stages of vocabulary development is still not fully understood. The Sound-Symbolism Bootstrapping Hypothesis (SSBH) proposes that sound-symbolism is essential for word learning to commence, but empirical evidence of exactly how sound-symbolism influences language learning is still sparse. It may be the case that sound-symbolism supports acquisition of categories of meaning, or that it enables acquisition of individualized word meanings. In two Experiments where participants learned form-meaning mappings from either sound-symbolic or arbitrary languages, we demonstrate the changing roles of sound-symbolism and arbitrariness for different vocabulary sizes, showing that sound-symbolism provides an advantage for learning of broad categories, which may then transfer to support learning individual words, whereas an arbitrary language impedes acquisition of categories of sound to meaning.

Abstract

We investigated whether alignment differences reported for Southern and Northern German speakers (Southerners align peaks in prenuclear accents later than Northerners) are carried over to the production of different functional categories such as contrast. To this end, the realisation of non-contrastive theme accents is compared with those in contrastive theme-rheme pairs such as ‘Sam rented a truck and Johanna rented a car.’
We found that when producing this ‘double-contrast’, speakers mark contrast both phonetically by delaying and rising the peak of the theme accent (‘Johanna’) and/or phonologically by a change in rheme accent type (from high to falling ‘car’).
The effect of dialect is complex: a) only in non-contrastive contexts produced with a high rheme accent Southerners align peaks later than Northerners; b) peak delay as a means to signal functional contrast is not used uniformly by the two varieties. Dialect clearly affects the realisation of prenuclear accents but its effect is conditioned by the pragmatic and intonational context.

Abstract

Two Cross-Modal Priming experiments assessed
lexical activation of unintended words for
nonnative (Dutch) and English native listeners.
Stimuli mismatched words in final voicing, which
in earlier studies caused spurious lexical activation
for Dutch listeners. The stimuli were embedded in
or cut out of a carrier (PRESident). The presence of
a longer lexical competitor in the signal or as a
possible continuation of it prevented spurious
lexical activation of mismatching words (press).

Abstract

Three 2AFC experiments investigated Dutch and English listeners’ use of preceding vowel duration for the English final /v/-/f/ contrast. Dutch listeners used vowel duration more flexibly than English listeners did: they could use vowel duration as accurately as native listeners, but were better at ignoring it when it was misleading.

Abstract

A Cross-Modal Priming experiment investigated Dutch
listeners’ perception of English words. Target words were
embedded in a carrier word (e.g., cat in catalogue) or ‘almost
embedded’ in a carrier word except for a mismatch in the
perceptually difficult /æ/-/ε/ contrast (e.g., cat in kettle).
Previous results showed a bias towards perception of /ε/ over
/æ/. The present study shows that presentation of carrier
words either containing an /æ/ or an /ε/ led to long lasting
inhibition of embedded or ‘almost embedded’ words with an
/æ/, but not of words with an /ε/. Thus, both catalogue and
kettle hindered recognition of cat, whereas neither schedule
nor shadow hindered recognition of shed.

Abstract

Research on second language acquisition typically focuses on how a first language (L1) influences a second language (L2) in different linguistic domains and across modalities. This dissertation, in contrast, explores interactions between languages in the mind of a language learner by asking 1) can an emerging L2 influence an established L1? 2) if so, how is such influence realized? 3) are there parallel influences of the L1 on the L2? These questions were investigated for the expression of Manner (e.g. climb, roll) and Path (e.g. up, down) of motion, areas where substantial crosslinguistic differences exist in speech and co-speech gesture. Japanese and English are typologically distinct in this domain; therefore, narrative descriptions of four motion events were elicited from monolingual Japanese speakers (n=16), monolingual English speakers (n=13), and native Japanese speakers with intermediate knowledge of English (narratives elicited in both their L1 and L2, n=28). Ways in which Path and Manner were expressed at the lexical, syntactic, and gestural levels were analyzed in monolingual and non-monolingual production. Results suggest mutual crosslinguistic influences. In their L1, native Japanese speakers with knowledge of English displayed both Japanese- and English-like use of morphosyntactic elements to express Path and Manner (i.e. a combination of verbs and other constructions). Consequently, non-monolingual L1 discourse contained significantly more Path expressions per clause, with significantly greater mention of Goal of motion than monolingual Japanese and English discourse. Furthermore, the gestures of non-monolingual speakers diverged from their monolingual counterparts with differences in depiction of Manner and gesture perspective (character versus observer). Importantly, non-monolingual production in the L1 was not ungrammatical, but simply reflected altered preferences. As for L2 production, many effects of L1 influence were seen, crucially in areas parallel to those described above. Overall, production by native Japanese speakers who knew English differed from that of monolingual Japanese and English speakers. But L1 and L2 production within non-monolingual individuals was similar. These findings imply a convergence of L1-L2 linguistic systems within the mind of a language learner. Theoretical and methodological implications for SLA research and language assessment with respect to the 'native speaker standard language' are discussed.

Abstract

Lexically guided perceptual learni ng refers to the use of lexical knowledge to retune sp eech categories and thereby adapt to a novel talker’s pronunciation. This adaptation has been extensively documented, but primarily for segmental-based learning in English and Dutch. In languages with lexical tone, such as Mandarin Chinese, tonal categories can also be retuned in this way, but segmental category retuning had not been studied. We report two experiment s in which Mandarin Chinese listeners were exposed to an ambiguous mixture of [f] and [s] in lexical contexts favoring an interpretation as either [f] or [s]. Listeners were subsequently more likely to identify sounds along a continuum between [f] and [s], and to interpret minimal word pairs, in a manner consistent with this exposure. Thus lexically guided perceptual learning of segmental categories had indeed taken place, consistent with suggestions that such learning may be a universally available adaptation process

Abstract

This paper reports on the first results of the DOBES project ‘Towards a multimedia dictionary of the Marquesan and Tuamotuan languages of French Polynesia’. Within the framework of this project we are building a digital multimedia encyclopedic lexicon of the endangered Marquesan and Tuamotuan languages using a new tool, LEXUS. LEXUS is a web-based lexicon tool, targeted at linguists involved in language documentation. LEXUS offers the possibility to visualize language. It provides functionalities to include audio, video and still images to the lexical entries of the dictionary, as well as relational linking for the creation of a semantic network knowledge base. Further activities aim at the development of (1) an improved user interface in close cooperation with the speech community and (2) a collaborative workspace functionality which will allow the speech community to actively participate in the creation of lexica.

Abstract

Interoperable annotation formats are fundamental to the utility, expansion, and sustainability of collective data repositories.In language development research, shared annotation schemes have been critical to facilitating the transition from raw acoustic data to searchable, structured corpora. Current schemes typically require comprehensive and manual annotation of utterance boundaries and orthographic speech content, with an additional, optional range of tags of interest. These schemes have been enormously successful for datasets on the scale of dozens of recording hours but are untenable for long-format recording corpora, which routinely contain hundreds to thousands of audio hours. Long-format corpora would benefit greatly from (semi-)automated analyses, both on the earliest steps of annotation—voice activity detection, utterance segmentation, and speaker diarization—as well as later steps—e.g., classification-based codes such as child-vs-adult-directed speech, and speech recognition to produce phonetic/orthographic representations. We present an annotation workflow specifically designed for long-format corpora which can be tailored by individual researchers and which interfaces with the current dominant scheme for short-format recordings. The workflow allows semi-automated annotation and analyses at higher linguistic levels. We give one example of how the workflow has been successfully implemented in a large cross-database project.

Abstract

Child-directed speech is argued to facilitate language development, and is found cross-linguistically and cross-culturally to varying degrees. However, previous research has generally focused on short samples of child-caregiver interaction, often in the lab or with experimenters present. We test the generalizability of this phenomenon with an initial descriptive analysis of the speech heard by young children in a large, unique collection of naturalistic, daylong home recordings. Trained annotators coded automatically-detected adult speech 'utterances' from 61 homes across 4 North American cities, gathered from children (age 2-24 months) wearing audio recorders during a typical day. Coders marked the speaker gender (male/female) and intended addressee (child/adult), yielding 10,886 addressee and gender tags from 2,523 minutes of audio (cf. HB-CHAAC Interspeech ComParE challenge; Schuller et al., in press). Automated speaker-diarization (LENA) incorrectly gender-tagged 30% of male adult utterances, compared to manually-coded consensus. Furthermore, we find effects of SES and gender on child-directed and overall speech, increasing child-directed speech with child age, and interactions of speaker gender, child gender, and child age: female caretakers increased their child-directed speech more with age than male caretakers did, but only for male infants. Implications for language acquisition and existing classification algorithms are discussed.

Abstract

We analysed intonation contours of two-word utterances from three monolingual Dutch children aged between 1;4 and 2;1 in the autosegmentalmetrical framework. Our data show that children have mastered the inventory of the boundary tones and nuclear pitch accent types (except for L*HL and L*!HL) at the 160-word level, and the set of nondownstepped pre-nuclear pitch accents (except for L*) at the 230-word level, contra previous claims on the mastery of adult-like intonation contours before or at the onset of first words. Further, there is evidence that intonational development is correlated with an increase in vocabulary size. Moreover, we found that children show a preference for falling contours, as predicted on the basis of universal production mechanisms. In addition, the utterances are mostly spoken with both words accented independent of semantic relations expressed and information status of each word across developmental stages, contra prior work. Our study suggests a number of topics for further research.

Abstract

This study examined how Dutch-acquiring 4- to 5-year-olds use different pitch accent types and deaccentuation to mark topic and focus at the sentence level and how they differ from adults. The topic and focus were non-contrastive and realised as full noun phrases. It was found that children realise topic and focus similarly frequently with H*L, whereas adults use H*L noticeably more frequently in focus than in topic in sentence-initial position and nearly only in focus in sentence-final position. Further, children frequently realise the topic with an accent, whereas adults mostly deaccent the sentence-final topic and use H*L and H* to realise the sentence-initial topic because of rhythmic motivation. These results show that 4- and 5-year-olds have not acquired H*L as the typical focus accent and deaccentuation as the typical topic intonation yet. Possibly, frequent use of H*L in sentence-initial topic in adult Dutch has made it difficult to extract the functions of H*L and deaccentuation from the input.

Abstract

We investigated how listeners of two unrelated languages, Dutch and Korean, process phonotactically legitimate and illegitimate sounds spoken in Dutch and American English. To Dutch listeners, unreleased word-final stops are phonotactically illegal because word-final stops in Dutch are generally released in isolation, but to Korean listeners, released final stops are illegal because word-final stops are never released in Korean. Two phoneme monitoring experiments showed a phonotactic effect: Dutch listeners detected released stops more rapidly than unreleased stops whereas the reverse was true for Korean listeners. Korean listeners with English stimuli detected released stops more accurately than unreleased stops, however, suggesting that acoustic-phonetic cues associated with released stops improve detection accuracy. We propose that in non-native speech perception, phonotactic legitimacy in the native language speeds up phoneme recognition, the richness of acousticphonetic cues improves listening accuracy, and familiarity with the non-native language modulates the relative influence of these two factors.

Abstract

The aim of this study was to determine if Dutch speakers reliably signal phrase-internal lexical boundaries, and if so, how. Six speakers recorded 4 pairs of phonemically identical strong-weak-strong (SWS) strings with matching syllable boundaries but mismatching intended word boundaries (e.g. reis # pastei versus reispas # tij, or more broadly C1V2(C)#C2V2(C)C3V3(C) vs. C1V2(C)C2V2(C)#C3V3(C)). An Analysis of Variance revealed 3 acoustic parameters that were significantly greater in S#WS items (C2 DURATION, RIME1 DURATION, C3 BURST AMPLITUDE) and 5 parameters that were significantly greater in the SW#S items (C2 VOT, C3 DURATION, RIME2 DURATION, RIME3 DURATION, and V2 AMPLITUDE). Additionally, center of gravity measurements suggested that the [s] to [t] coarticulation was greater in reis # pa[st]ei versus reispa[s] # [t]ij. Finally, a Logistic Regression Analysis revealed that the 3 parameters (RIME1 DURATION, RIME2 DURATION, and C3 DURATION) contributed most reliably to a S#WS versus SW#S classification.

Abstract

The fluent production of speech is a very complex human skill. It requires the coordination of several articulatory subsystems. The instructions that lead articulatory movements to execution are the result of the interplay of speech production levels that operate above the articulatory network. During the process of word-form encoding, the groundwork for the articulatory programs is prepared which then serve the articulators as basic units. This thesis investigated whether or not syllables form the basis for the articulatory programs and in particular whether or not these syllable programs are stored, separate from the store of the lexical word-forms. It is assumed that syllable units are stored in a so-called 'mental syllabary'. The main goal of this thesis was to find evidence of the syllable playing a functionally important role in speech production and for the assumption that syllables are stored units. In a variant of the implicit priming paradigm, it was investigated whether information about the syllabic structure of a target word facilitates the preparation (advanced planning) of a to-be-produced utterance. These experiments yielded evidence for the functionally important role of syllables in speech production. In a subsequent row of experiments, it could be demonstrated that the production of syllables is sensitive to frequency. Syllable frequency effects provide strong evidence for the notion of a mental syllabary because only stored units are likely to exhibit frequency effects. In a last study, effects of syllable preparation and syllable frequency were investigated in a combined study to disentangle the two effects. The results of this last experiment converged with those reported for the other experiments and added further support to the claim that syllables play a core functional role in speech production and are stored in a mental syllabary.

Abstract

We report an investigation of the perception of American English phonemes by Dutch listeners proficient in English. Listeners identified either the consonant or the vowel in most possible English CV and VC syllables. The syllables were embedded in multispeaker babble at three signal-to-noise ratios (16 dB, 8 dB, and 0 dB). Effects of signal-to-noise ratio on vowel and consonant identification are discussed as a function of syllable position and of relationship to the native phoneme inventory. Comparison of the results with previously reported data from native listeners reveals that noise affected the responding of native and non-native listeners similarly.

Abstract

Speaker diarization (answering 'who spoke when') is a widely researched subject within speech technology. Numerous experiments have been run on datasets built from broadcast news, meeting data, and call centers—the task sometimes appears close to being solved. Much less work has begun to tackle the hardest diarization task of all: spontaneous conversations in real-world settings. Such diarization would be particularly useful for studies of language acquisition, where researchers investigate the speech children produce and hear in their daily lives. In this paper, we study audio gathered with a recorder worn by small children as they went about their normal days. As a result, each child was exposed to different acoustic environments with a multitude of background noises and a varying number of adults and peers. The inconsistency of speech and noise within and across samples poses a challenging task for speaker diarization systems, which we tackled via retraining and data augmentation techniques. We further studied sources of structured variation across raw audio files, including the impact of speaker type distribution, proportion of speech from children, and child age on diarization performance. We discuss the extent to which these findings might generalize to other samples of speech in the wild.

Abstract

Language-specific differences in the size and distribution of the phonemic repertoire can have implications for the task facing listeners in recognising spoken words. A language with more phonemes will allow shorter words and reduced embedding of short words within longer ones, decreasing the potential for spurious lexical competitors to be activated by speech signals. We demonstrate that this is the case via comparative analyses of the vocabularies of English and Spanish. A language which uses suprasegmental as well as segmental contrasts, however, can substantially reduce the extent of spurious embedding.

Abstract

Assimilation of place of articulation across a nasal and a following stop consonant is obligatory in Japanese, but not in Dutch. In four experiments the processing of assimilated forms by speakers of Japanese and Dutch was compared, using a task in which listeners blended pseudo-word pairs such as ranga-serupa. An assimilated blend of this pair would be rampa, an unassimilated blend rangpa. Japanese listeners produced significantly more assimilated than unassimilated forms, both with pseudo-Japanese and pseudo-Dutch materials, while Dutch listeners produced significantly more unassimilated than assimilated forms in each materials set. This suggests that Japanese listeners, whose native-language phonology involves obligatory assimilation constraints, represent the assimilated nasals in nasal-stop sequences as unmarked for place of articulation, while Dutch listeners, who are accustomed to hearing unassimilated forms, represent the same nasal segments as marked for place of articulation.

Abstract

In two experiments, Mandarin listeners resolved potential syntactic ambiguities in spoken utterances in (a) their native language (L1) and (b) English which they had learned as a second language (L2). A new disambiguation task was used, requiring speeded responses to select the correct meaning for structurally ambiguous sentences. Importantly, the ambiguities used in the study are identical in Mandarin and in English, and production data show that prosodic disambiguation of this type of ambiguity is also realised very similarly in the two languages. The perceptual results here showed however that listeners’ response patterns differed for L1 and L2, although there was a significant increase in similarity between the two response patterns with increasing exposure to the L2. Thus identical ambiguity and comparable disambiguation patterns in L1 and L2 do not lead to immediate application of the appropriate L1 listening strategy to L2; instead, it appears that such a strategy may have to be learned anew for the L2.

Abstract

The perceptual processing of speech is a constant interplay of multiple competing albeit convergent processes: acoustic input vs. higher-level representations, universal mechanisms vs. language-specific, veridical traces of speech experience vs. construction and activation of abstract representations. The present summary concerns the third of these issues. The ability to generalise across experience and to deal with resulting abstractions is the hallmark of human cognition, visible even in early infancy. In speech processing, abstract representations play a necessary role in both production and perception. New sorts of evidence are now informing our understanding of the breadth of this role.

Abstract

Using a phoneme detection task, the present series of
experiments examines whether listeners can entrain to
different combinations of prosodic cues to predict where focus
will fall in an utterance. The stimuli were recorded by four
female native speakers of Australian English who happened to
have used different prosodic cues to produce sentences with
prosodic focus: a combination of duration cues, mean and
maximum F0, F0 range, and longer pre-target interval before
the focused word onset, only mean F0 cues, only pre-target
interval, and only duration cues. Results revealed that listeners
can entrain in almost every condition except for where
duration was the only reliable cue. Our findings suggest that
listeners are flexible in the cues they use for focus processing.

Abstract

Dutch listeners outperform native listeners in identifying syllable stress in English. This is because lexical stress is more useful in recognition of spoken words of Dutch than of English, so that Dutch listeners pay greater attention to stress in general. We examined Dutch listeners’ use of the acoustic correlates of English stress. Primary- and secondary-stressed syllables differ significantly on acoustic measures, and some differences, in F0 especially, correlate with data of earlier listening experiments. The correlations found in the Dutch responses were not paralleled in data from native listeners. Thus the acoustic cues which distinguish English primary versus secondary stress are better exploited by Dutch than by native listeners.

Abstract

In English and Dutch, listeners entrain to prosodic contours to predict where focus will fall in an utterance. However, is this strategy universally available, even in languages with different phonological systems? In a phoneme detection experiment, we examined whether prosodic entrainment is also found in Mandarin Chinese, a tone language, where in principle the use of pitch for lexical identity may take precedence over the use of pitch cues to salience. Consistent with the results from Germanic languages, response times were facilitated when preceding intonation predicted accent on the target-bearing word. Acoustic analyses revealed greater F0 range in the preceding intonation of the predicted-accent sentences. These findings have implications for how universal and language-specific mechanisms interact in the processing of salience.

Abstract

In contrast to initial L1 vocabularies, which of necessity depend largely on heard exemplars, L2 vocabulary construction can draw on a variety of knowledge sources. This can lead to richer stored knowledge about the phonology of the L2 than the listener's prelexical phonetic processing capacity can support, and thus to mismatch between the level of detail required for accurate lexical mapping and the level of detail delivered by the prelexical processor. Experiments on spoken word recognition in L2 have shown that phonetic contrasts which are not reliably perceived are represented in the lexicon nonetheless. This lexical representation of contrast must be based on abstract knowledge, not on veridical representation of heard exemplars. New experiments confirm that provision of abstract knowledge (in the form of spelling) can induce lexical representation of a contrast which is not reliably perceived; but also that experience (in the form of frequency of occurrence) modulates the mismatch of phonetic and lexical processing. We conclude that a correct account of word recognition in L2 (as indeed in L1) requires consideration of both abstract and episodic information.

Abstract

The difficulty of listening to speech in noise is exacerbated when the speech is in the listener’s L2 rather than L1. In this study, Spanish and Dutch users of English as an L2 identified American English consonants in a constant intervocalic context. Their performance was compared with that of L1 (British English) listeners, under quiet conditions and when the speech was masked by speech from another talker or by noise. Masking affected performance more for the Spanish listeners than for the L1 listeners, but not for the Dutch listeners, whose performance was worse than the L1 case to about the same degree in all conditions. There were, however,large differences in the pattern of results across individual consonants, which were consistent with differences in how consonants are identified in the respective L1s.

Abstract

Listeners adapt rapidly to previously unheard talkers by
adjusting phoneme categories using lexical knowledge, in a
process termed lexically-guided perceptual learning. Although
this is firmly established for listening in the native language
(L1), perceptual flexibility in second languages (L2) is as yet
less well understood. We report two experiments examining L1
and L2 perceptual learning, the first in Mandarin-English late
bilinguals, the second in Australian learners of Mandarin. Both
studies showed stronger learning in L1; in L2, however,
learning appeared for the English-L1 group but not for the
Mandarin-L1 group. Phonological mapping differences from
the L1 to the L2 are suggested as the reason for this result.

Abstract

Languages contain tens of thousands of words, but these are constructed from a tiny handful of phonetic elements. Consequently, words resemble one another, or can be embedded within one another, a coup stick snot with standing. me process of spoken-word recognition by human listeners involves activation of multiple word candidates consistent with the input, and direct competition between activated candidate words. Further, human listeners are sensitive, at an early, prelexical, stage of speeeh processing, to constraints on what could potentially be a word of the language.

Abstract

The phoneme detection task is widely used in spoken word recognition research. Alphabetically literate participants, however, are more used to explicit representations of letters than of phonemes. The present study explored whether phoneme detection is sensitive to how target phonemes are, or may be, orthographically realised. Listeners detected the target sounds [b,m,t,f,s,k] in word-initial position in sequences of isolated English words. Response times were faster to the targets [b,m,t], which have consistent word-initial spelling, than to the targets [f,s,k], which are inconsistently spelled, but only when listeners’ attention was drawn to spelling by the presence in the experiment of many irregularly spelled fillers. Within the inconsistent targets [f,s,k], there was no significant difference between responses to targets in words with majority and minority spellings. We conclude that performance in the phoneme detection task is not necessarily sensitive to orthographic effects, but that salient orthographic manipulation can induce such sensitivity.

Abstract

Two lexical decision experiments in Cantonese are described in which the recognition of spoken target words as a function of phonological similarity to a preceding prime is investigated. Phonological similaritv in first syllables produced inhibition, while similarity in second syllables led to facilitation. Differences between syllables in tonal and segmental structure had generally similar effects.

Abstract

Responding to similarity, difference, and relative magnitude (SDM) is ubiquitous in the animal kingdom. However, humans seem unique in the ability to represent relative magnitude (‘more’/‘less’) and similarity (‘same’/‘different’) as abstract relations that take arguments (e.g., greater-than (x,y)). While many models use structured relational representations of magnitude and similarity, little progress has been made on how these representations arise. Models that developuse these representations assume access to computations of similarity and magnitude a priori, either encoded as features or as output of evaluation operators. We detail a mechanism for producing invariant responses to “same”, “different”, “more”, and “less” which can be exploited to compute similarity and magnitude as an evaluation operator. Using DORA (Doumas, Hummel, & Sandhofer, 2008), these invariant responses can serve be used to learn structured relational representations of relative magnitude and similarity from pixel images of simple shapes

Abstract

This paper summarizes the results of a descriptive syntactic category analysis of child English no which reveals that young children use and represent no as a determiner and negatives like no pen as NPs, contra standard analyses.

Abstract

Biologically inspired spiking networks are an important tool to study the nature of computation and cognition in neural systems. In this work, we investigate the representational capacity of spiking networks engaged in an identity mapping task. We compare two schemes for encoding symbolic input, one in which input is injected as a direct current and one where input is delivered as a spatio-temporal spike pattern. We test the ability of networks to discriminate their input as a function of the number of distinct input symbols. We also compare performance using either membrane potentials or filtered spike trains as state variable. Furthermore, we investigate how the circuit behavior depends on the balance between excitation and inhibition, and the degree of synchrony and regularity in its internal dynamics. Finally, we compare different linear methods of decoding population activity onto desired target labels. Overall, our results suggest that even this simple mapping task is strongly influenced by design choices on input encoding, state-variables, circuit characteristics and decoding methods, and these factors can interact in complex ways. This work highlights the importance of constraining computational network models of behavior by available neurobiological evidence.

Abstract

We report the results of a large-scale (N=1571) experiment to investigate whether spoken words can emerge from the process of repeated imitation. Participants played a version of the children’s game “Telephone”. The first generation was asked to imitate recognizable environmental sounds (e.g., glass breaking, water splashing); subsequent generations imitated the imitators for a total of 8 generations. We then examined whether the vocal imitations became more stable and word-like, retained a resemblance to the original sound, and became more suitable as learned category labels. The results showed (1) the imitations became progressively more word-like, (2) even after 8 generations, they could be matched above chance to the environmental sound that motivated them, and (3) imitations from later generations were more effective as learned category labels. These results show how repeated imitation can create progressively more word-like forms while retaining a semblance of iconicity.

Abstract

This study addresses the roles of segment deletion, durational reduction, and frequency of use in the comprehension of morphologically complex words. We report two auditory lexical decision experiments with reduced and unreduced prefixed Dutch words. We found that segment deletions as such delayed comprehension. Simultaneously, however, longer durations of the different parts of the words appeared to increase lexical competition, either from the word’s stem (Experiment 1) or from the word’s morphological continuation forms (Experiment 2). Increased lexical competition slowed down especially the comprehension of low frequency words, which shows that speakers do not try to meet listeners’ needs when they reduce especially high frequency words.

Abstract

One of the most daunting tasks of a listener is to map a
continuous auditory stream onto known speech sound
categories and lexical items. A major issue with this mapping
problem is the variability in the acoustic realizations of sound
categories, both within and across speakers. Past research has
suggested listeners may use visual information (e.g., lipreading)
to calibrate these speech categories to the current
speaker. Previous studies have focused on audiovisual
recalibration of consonant categories. The present study
explores whether vowel categorization, which is known to show
less sharply defined category boundaries, also benefit from
visual cues.
Participants were exposed to videos of a speaker
pronouncing one out of two vowels, paired with audio that was
ambiguous between the two vowels. After exposure, it was
found that participants had recalibrated their vowel categories.
In addition, individual variability in audiovisual recalibration is
discussed. It is suggested that listeners’ category sharpness may
be related to the weight they assign to visual information in
audiovisual speech perception. Specifically, listeners with less
sharp categories assign more weight to visual information
during audiovisual speech recognition.

Abstract

Speaking and listening are complex tasks that we perform on a daily basis, almost without conscious effort. Interestingly, speaking almost never occurs without listening: whenever we speak, we at least hear our own speech. The research in this thesis is concerned with how the perception of our own speech influences our speaking behavior. We show that unconsciously, we actively monitor this auditory feedback of our own speech. This way, we can efficiently take action and adapt articulation when an error occurs and auditory feedback does not correspond to our expectation. Processing the auditory feedback of our speech does not, however, automatically affect speech production. It is subject to a number of constraints. For example, we do not just track auditory feedback, but also its consistency. If auditory feedback is more consistent over time, it has a stronger influence on speech production. In addition, we investigated how auditory feedback during speech is processed in the brain, using magnetoencephalography (MEG). The results suggest the involvement of a broad cortical network including both auditory and motor-related regions. This is consistent with the view that the auditory center of the brain is involved in comparing auditory feedback to our expectation of auditory feedback. If this comparison yields a mismatch, motor-related regions of the brain can be recruited to alter the ongoing articulations.

Abstract

A crucial aspect of everyday conversational interactions is our ability to establish and maintain common ground. Understanding the relevant mechanisms involved in such social coordination remains an important challenge for cognitive science. While common ground is often discussed in very general terms, different contexts of interaction are likely to afford different coordination mechanisms. In this paper, we investigate the presence and relation of three mechanisms of social coordination – backchannels, interactive alignment and conversational repair – across free and task-oriented conversations. We find significant differences: task-oriented conversations involve higher presence of repair – restricted offers in particular – and backchannel, as well as a reduced level of lexical and syntactic alignment. We find that restricted repair is associated with lexical alignment and open repair with backchannels. Our findings highlight the need to explicitly assess several mechanisms at once and to investigate diverse activities to understand their role and relations.

Abstract

We analyze the problem of response suggestion in a closed domain along a real-world scenario of a digital library. We present a text-processing pipeline to generate question-answer pairs from chat transcripts. On this limited amount of training data, we compare retrieval-based, conditioned-generation, and dedicated representation learning approaches for response suggestion. Our results show that retrieval-based methods that strive to find similar, known contexts are preferable over parametric approaches from the conditioned-generation family, when the training data is limited. We, however, identify a specific representation learning approach that is competitive to the retrieval-based approaches despite the training data limitation.

Abstract

We present multi-modal adversarial autoencoders for recommendation and evaluate them on two different tasks: citation recommendation and subject label recommendation. We analyze the effects of adversarial regularization, sparsity, and different input modalities. By conducting 408 experiments, we show that adversarial regularization consistently improves the performance of autoencoders for recommendation. We demonstrate, however, that the two tasks differ in the semantics of item co-occurrence in the sense that item co-occurrence resembles relatedness in case of citations, yet implies diversity in case of subject labels. Our results reveal that supplying the partial item set as input is only helpful, when item co-occurrence resembles relatedness. When facing a new recommendation task it is therefore crucial to consider the semantics of item co-occurrence for the choice of an appropriate model.

Abstract

We conduct the first systematic comparison of automated semantic
annotation based on either the full-text or only on the title metadata
of documents. Apart from the prominent text classification baselines
kNN and SVM, we also compare recent techniques of Learning
to Rank and neural networks and revisit the traditional methods
logistic regression, Rocchio, and Naive Bayes. Across three of our
four datasets, the performance of the classifications using only titles
reaches over 90% of the quality compared to the performance when
using the full-text.

Abstract

We assess the suitability of word embeddings for practical information retrieval scenarios. Thus, we assume that users issue ad-hoc short queries where we return the first twenty retrieved documents after applying a boolean matching operation between the query and the documents. We compare the performance of several techniques that leverage word embeddings in the retrieval models to compute the similarity between the query and the documents, namely word centroid similarity, paragraph vectors, Word Mover’s distance, as well as our novel inverse document frequency (IDF) re-weighted word centroid similarity. We evaluate the performance using the ranking metrics mean average precision, mean reciprocal rank, and normalized discounted cumulative gain. Additionally, we inspect the retrieval models’ sensitivity to document length by using either only the title or the full-text of the documents for the retrieval task. We conclude that word centroid similarity is the best competitor to state-of-the-art retrieval models. It can be further improved by re-weighting the word frequencies with IDF before aggregating the respective word vectors of the embedding. The proposed cosine similarity of IDF re-weighted word vectors is competitive to the TF-IDF baseline and even outperforms it in case of the news domain with a relative percentage of 15%.

Abstract

This doctoral dissertation investigated the learning of auditory categories by applying insights from child language learning, visual category learning and phonetic categorization by adults. The experiments in chapter 2 concern supervised learning of multidimensional non-speech categories varying in two dimensions: duration and a non speech analogue of formant frequency. In experiment 1, one dimension of variation determined category membership, variation in the other dimension was irrelevant. Listeners quickly learned to categorize according to this distinction. In experiment 2, both dimensions needed to be combined to categorize correctly. Performance was much lower, but most listeners succeeded in this task. However, in a maintenance phase without feedback or distributional information, listeners reverted to a unidimensional solution. In a maintenance phase with distributional information, listeners did use both dimensions correctly, arguing for the importance of distributional information in (auditory) category acquisition. In chapter 3, the listeners had to classify the same categories, but without feedback. In experiment 1, listeners succeeded to discover the relevant dimension of variation (and ignore the irrelevant one) without feedback. Much of this learning was lost in the maintenance phase, especially for the dimension formant frequency. With two relevant dimensions (Experiment 2), listeners were not able to learn to use both dimensions and reverted to a unidimensional solution. Chapter 4 applied the paradigms of chapter 2 and 3 to the learning of speech categories. Spanish native listeners learned Dutch vowel contrast with one relevant dimension of variation. With feedback, learning was swift, although was not well maintained without feedback or distributional information. Without feedback, Spanish listeners reverted to the dimensions best known in their native phonology, formant frequency, even when distributional information pointed to duration. The results are discussed in chapter 5. The implications for models of speech acquisition are discussed.

Abstract

Distributional learning is almost certainly involved in the human acquisition of phonetic categories. Because speech is inherently a multidimensional signal, learning phonetic categories entails multidimensional learning. Yet previous studies of auditory category learning have shown poor maintenance of learned multidimensional categories. Two experiments explored ways to improve maintenance: by increasing the costs associated with applying a unidimensional strategy; by providing additional information about the category structures; and by giving explicit instructions on how to categorize. Only with explicit instructions were categorization strategies maintained in a maintenance phase without supervision or distributional information.

Abstract

Syntactic parsers and generators need highquality grammars of coordination and coordinate ellipsis—structures that occur very frequently but are much less well understood theoretically than many other domains of grammar. Modern grammars of coordinate ellipsis are based nearly exclusively on linguistic judgments (intuitions). The extent to which grammar rules based on this type of empirical evidence generate all and only the structures in text corpora, is unknown. As part of a project on the development of a grammar and a generator for coordinate ellipsis in German, we undertook an extensive exploration of the TIGER treebank—a syntactically annotated corpus of about 50,000 newspaper sentences. We report (1) frequency data for the various patterns of coordinate ellipsis, and (2) several rarely (but regularly) occurring ‘fringe deviations’ from the intuition-based rules for several ellipsis types. This information can help improve parser and generator performance.

Abstract

The potential of sentence generators as engines in Intelligent Computer-Assisted Language Learning and teaching (ICALL) software has hardly been explored. We sketch the prototype of COMPASS, a system that supports integrated writing and grammar curricula for 10 to 14 year old elementary or secondary schoolers. The system enables first- or second-language teachers to design controlled writing exercises, in particular of the “sentence combining” variety. The system includes facilities for error diagnosis and on-line feedback. Syntactic structures built by students or system can be displayed as easily understood phrase-structure or dependency trees, adapted to the student’s level of grammatical knowledge. The heart of the system is a specially designed generator capable of lexically guided sentence generation, of generating syntactic paraphrases, and displaying syntactic structures visually.

Abstract

This thesis elaborates on a methodological approach to reliably infer cognitive preferences in an extinct evolutionary ancestor of modern humans. In attempts to understand cognitive evolution, humans have been compared to capuchin monkeys, tamarins, and chimpanzees to name but a few. But comparisons between humans and one other, maybe even distantly related primate, as interesting as they might be, will not tell us anything about an evolutionary ancestor to humans. To put it bluntly: None of the living primates, not even chimpanzees, are a human ancestor. With that in mind, we can still use a comparative approach to gain information about our evolutionary ancestors, as long as we are careful about whom we compare with whom. If a certain trait exists in all genera of a phylogenetic clade, it was most likely present in their common ancestor. The great apes are such a clade (Pongo, Gorilla, Pan and Homo). It follows that, if members of all great ape genera shared a particular cognitive preference or ability, it is most likely part of the evolutionary inheritance of the clade at least ever since their last common ancestor, and therefore also an evolutionarily old, inherited cognitive default in humans. This thesis contains studies comparing all 4 extant Hominid genera, including humans of 4 different age-groups and 2 different cultures. Results show that all great apes do indeed share some cognitive preferences, which they most likely inherited from an evolutionary ancestor. Additionally, human cognitive preferences can change away from such an inherited predisposition given ontogenetic factors, and are at least in part variably adaptable to cultural circumstance.

Abstract

This paper reports on findings from an elicited production task with German 5-year-old children, investigating their use of intonation to mark information status of discourse referents. In line with findings for adults, new referents were preferably marked by H* and L+H*; textually given referents were mainly deaccented. Accessible referents (whose first mentions were less recent) were mostly accented, and predominantly also realised with H* and L+H*, showing children’s sensitivity to recency of mention. No evidence for the consistent use of a special ‘accessibility accent’ H+L* (as has been proposed for adult German) was found.

Abstract

What makes some words harder to learn than others in a second language? Although some robust factors have been identified based on small scale experimental studies, many relevant factors are difficult to study in such experiments due to the amount of data necessary to test them. Here, we investigate what factors affect the ease of learning of a word in a second language using a large data set of users learning English as a second language through the Duolingo mobile app. In a regression analysis, we test and confirm the well-studied effect of cognate status on word learning accuracy. Furthermore, we find significant effects for both cross-linguistic semantic alignment and English semantic density, two novel predictors derived from large scale distributional models of lexical semantics. Finally, we provide data on several other psycholinguistically plausible word level predictors. We conclude with a discussion of the limits, benefits and future research potential of using big data for investigating second language learning.