Publications

Abstract

Words are often pronounced with fewer segments in casual conversations than in formal speech. Previous research has shown that foreign language learners and beginning second language learners experience problems processing reduced speech. We examined whether this also holds for advanced second language learners. We designed a dictation task in Dutch consisting of sentences spliced from casual conversations and an unreduced counterpart of this task, with the same sentences carefully articulated by the same speaker. Advanced second language learners of Dutch produced substantially more transcription errors for the reduced than for the unreduced sentences. These errors made the sentences incomprehensible or led to non-intended meanings. The learners often did not rely on the semantic and syntactic information in the sentence or on the subsegmental cues to overcome the reductions. Hence, advanced second language learners also appear to suffer from the reduced pronunciation variants of words that are abundant in everyday conversations

Abstract

This study investigates how the comprehension of casual speech in foreign languages is affected by the phonotactic constraints in the listener’s native language. Non-native listeners of English with different native languages heard short English phrases produced by native speakers of English or Spanish and they indicated whether these phrases included can or can’t. Native Mandarin listeners especially tended to interpret can’t as can. We interpret this result as a direct effect of the ban on word-final /nt/ in Mandarin. Both the native Mandarin and the native Spanish listeners did not take full advantage of the subsegmental information in the speech signal cueing reduced can’t. This finding is probably an indirect effect of the phonotactic constraints in their native languages: these listeners have difficulties interpreting the subsegmental cues because these cues do not occur or have different functions in their native languages. Dutch resembles English in the phonotactic constraints relevant to the comprehension of can’t, and native Dutch listeners showed similar patterns in their comprehension of native and non-native English to native English listeners. This result supports our conclusion that the major patterns in the comprehension results are driven by the phonotactic constraints in the listeners’ native languages.

Abstract

This paper investigates the processes in comprehending spoken noun-noun compounds, using data from the BALDEY database. BALDEY contains lexicality judgments and reaction times (RTs) for Dutch stimuli for which also linguistic information is included. Two different approaches are combined. The first is based on regression by Dynamic Survival Analysis, which models decisions and RTs as a consequence of the fact that a cumulative density function exceeds some threshold. The parameters of that function are estimated from the observed RT data. The second approach is based on DIANA, a process-oriented computational model of human word comprehension, which simulates the comprehension process with the acoustic stimulus as input. DIANA gives the identity and the number of the word candidates that are activated at each 10 ms time step.

Both approaches show how the processes involved in comprehending compounds change during a stimulus. Survival Analysis shows that the impact of word duration varies during the course of a stimulus. The density of word and non-word hypotheses in DIANA shows a corresponding pattern with different regimes. We show how the approaches complement each other, and discuss additional ways in which data and process models can be combined.

Abstract

Previous work has shown that novel morphologically complex words (henceforth neologisms) leave traces in memory after just one encounter. This study addressed the question whether these traces are abstract in nature or exemplars. In three experiments, neologisms were either primed by themselves or by their stems. The primes occurred in the visual modality whereas the targets were presented in the auditory modality (Experiment 1) or vice versa (Experiments 2 and 3). The primes were presented in sentences in a selfpaced reading task (Experiment 1) or in stories in a listening comprehension task (Experiments 2 and 3). The targets were incorporated in lexical decision tasks, auditory or visual (Experiment 1 and Experiment 2, respectively), or in stories in a self-paced reading task (Experiment 3). The experimental part containing the targets immediately followed the familiarization phase with the primes (Experiment 1), or after a one week delay (Experiments 2 and 3). In all experiments, participants recognized neologisms faster if they had encountered them before (identity priming) than if the familiarization phase only contained the neologisms’ stems (stem priming). These results show that the priming effects are robust despite substantial differences between the primes and the targets. This suggests that the traces novel morphologically complex words leave in memory after just one encounter are abstract in nature.

Abstract

This electrophysiological study asked whether the brain processes grammatical gender
violations in casual speech differently than in careful speech. Native speakers of Dutch were
presented with utterances that contained adjective-noun pairs in which the adjective was either
correctly inflected with a word-final schwa (e.g. een spannende roman “a suspenseful novel”) or
incorrectly uninflected without that schwa (een spannend roman). Consistent with previous
findings, the uninflected adjectives elicited an electrical brain response sensitive to syntactic
violations when the talker was speaking in a careful manner. When the talker was speaking in a
casual manner, this response was absent. A control condition showed electrophysiological responses
for carefully as well as casually produced utterances with semantic anomalies, showing that
listeners were able to understand the content of both types of utterance. The results suggest that
listeners take information about the speaking style of a talker into account when processing the
acoustic-phonetic information provided by the speech signal. Absent schwas in casual speech are
effectively not grammatical gender violations. These changes in syntactic processing are evidence
of contextually-driven neural flexibility.

Abstract

Rede uitgesproken bij de aanvaarding van het ambt van hoogleraar Psycholinguïstiek aan de Faculteit der Letteren van de Radboud Universiteit Nijmegen op vrijdag 18 januari 2013

Abstract

This paper studies the robustness of exemplar effects in word comprehension by means of four long-term priming experiments with lexical decision tasks in Dutch. A prime and target represented the same word type and were presented with the same or different degree of reduction. In Experiment 1, participants heard only a small number of trials, a large proportion of repeated words, and stimuli produced by only one speaker. They recognized targets more quickly if these represented the same degree of reduction as their primes, which forms additional evidence for the exemplar effects reported in the literature. Similar effects were found for two speakers who differ in their pronunciations. In Experiment 2, with a smaller proportion of repeated words and more trials between prime and target, participants recognized targets preceded by primes with the same or a different degree of reduction equally quickly. Also, in Experiments 3 and 4, in which listeners were not exposed to one but two types of pronunciation variation (reduction degree and speaker voice), no exemplar effects arose. We conclude that the role of exemplars in speech comprehension during natural conversations, which typically involve several speakers and few repeated content words, may be smaller than previously assumed.

Abstract

This paper investigates the nature of reduction phenomena in informal speech. It addresses the question whether reduction processes that affect many word types, but only if they occur in connected informal speech, may be categorical in nature. The focus is on reduction of schwa in the prefixes and on word-final /t/ in Dutch past participles. More than 2000 tokens of past participles from the Ernestus Corpus of Spontaneous Dutch and the Spoken Dutch Corpus (both from the interview and read speech component) were transcribed automatically. The results demonstrate that the presence and duration of /t/ are affected by approximately the same phonetic variables, indicating that the absence of /t/ is the extreme result of shortening, and thus results from a gradient reduction process. Also for schwa, the data show that mainly phonetic variables influence its reduction, but its presence is affected by different and more variables than its duration, which suggests that the absence of schwa may result from gradient as well as categorical processes. These conclusions are supported by the distributions of the segments’ durations. These findings provide evidence that reduction phenomena which affect many words in informal conversations may also result from categorical reduction processes.

Abstract

An audio and video corpus of speech addressed to 28 11-month-olds is described. The corpus allows comparisons between adult speech directed towards infants, familiar adults and unfamiliar adult addressees, as well as of caregivers’ word teaching strategies across word classes. Summary data show that infant-directed speech differed more from speech to unfamiliar than familiar adults; that word teaching strategies for nominals versus verbs and adjectives differed; that mothers mostly addressed infants with multi-word utterances; and that infants’ vocabulary size was unrelated to speech rate, but correlated positively with predominance of continuous caregiver speech (not of isolated words) in the input.

Abstract

Hoewel de spelling van Nederlandse verledentijdsvormen van zwakke werkwoorden algemeen als eenvoudig wordt beschouwd (ze zijn immers klankzuiver) maken zelfs universiteitsstudenten opvallend veel fouten bij de keuze tussen de uitgangen -te en -de. Voor een deel zijn die fouten ‘natuurlijk’ in die zin dat ze het gevolg zijn van de werking van frequentie en analogie. Anderzijds stellen we vast dat Nederlanders veel meer fouten maken dan Vlamingen, althans als de stam op een coronale fricatief eindigt (s, z, f, v). Aangezien de Nederlandse proefpersonen de ‘regel’ (het ezelsbruggetje ’t kofschip) beter lijken te beheersen dan de Vlamingen, moet de verklaring voor het verschil gezocht worden in een klankverandering die zich wel in Nederland maar niet of nauwelijks in Vlaanderen voordoet, de verstemlozing van de fricatieven. Het spellingprobleem vraagt om didactische maatregelen en/of politieke: het kan wellicht grotendeels worden opgelost door de spellingregels een weinig aan te passen.

Abstract

This paper describes a computational model of speech comprehension that takes the acoustic signal as input and predicts reaction times as observed in an auditory lexical decision task. By doing so, we explore a new generation of end-to-end computational models that are able to simulate the behaviour of human subjects participating in a psycholinguistic experiment. So far, nearly all computational models of speech comprehension do not start from the speech signal itself, but from abstract representations of the speech signal, while the few existing models that do start from the acoustic signal cannot directly model reaction times as obtained in comprehension experiments. The main functional components in our model are the perception stage, which is compatible with the psycholinguistic model Shortlist B and is implemented with techniques from automatic speech recognition, and the decision stage, which is based on the linear ballistic accumulation decision model. We successfully tested our model against data from 20 participants performing a largescale auditory lexical decision experiment. Analyses show that the model is a good predictor for the average judgment and reaction time for each word.

Abstract

Previous research has shown that the production of morphologically complex words in isolation is affected by the properties of morphologically, phonologically, or semantically similar words stored in the mental lexicon. We report five experiments with Dutch speakers that show that reading an inflectional word form in its linguistic context is also affected by analogical sets of formally similar words. Using the self-paced reading technique, we show in Experiments 1-3 that an incorrectly spelled suffix delays readers less if the incorrect spelling is in line with the spelling of verbal suffixes in other inflectional forms of the same verb. In Experiments 4 and 5, our use of the self-paced reading technique shows that formally similar words with different stems affect the reading of incorrect suffixal allomorphs on a given stem. These intra- and interparadigmatic effects in reading may be due to online processes or to the storage of incorrect forms resulting from analogical effects in production.

Abstract

Previous work has shown that Dutch listeners use prosodic information in the speech signal to optimise morphological processing: Listeners are sensitive to prosodic differences between a noun stem realised in isolation and a noun stem realised as part of a plural form (in which the stem is followed by an unstressed syllable). The present study, employing a lexical decision task, provides an additional demonstration of listeners' sensitivity to prosodic cues in the stem. This sensitivity is shown for two languages that differ in morphological productivity: Dutch and English. The degree of morphological productivity does not correlate with listeners' sensitivity to prosodic cues in the stem, but it is reflected in differential sensitivities to the word-specific log odds ratio of encountering an unshortened stem (i.e., a stem in isolation) versus encountering a shortened stem (i.e., a stem followed by a suffix consisting of one or more unstressed syllables). In addition to being sensitive to the prosodic cues themselves, listeners are also sensitive to the probabilities of occurrence of these prosodic cues.

Abstract

It has recently been shown that listeners use systematic differences in vowel length and intonation to resolve ambiguities between onset-matched simple words (Davis, Marslen-Wilson, & Gaskell, 2002; Salverda, Dahan, & McQueen, 2003). The present study shows that listeners also use prosodic information in the speech signal to optimize morphological processing. The precise acoustic realization of the stem provides crucial information to the listener about the morphological context in which the stem appears and attenuates the competition between stored inflectional variants. We argue that listeners are able to make use of prosodic information, even though the speech signal is highly variable within and between speakers, by virtue of the relative invariance of the duration of the onset. This provides listeners with a baseline against which the durational cues in a vowel and a coda can be evaluated. Furthermore, our experiments provide evidence for item-specific prosodic effects.

Abstract

In Dutch, high-frequency words with the suffix -lijk are often highly reduced in spontaneous unscripted speech. This study addressed socio-geographic variation in the reduction of such words against the backdrop of the variation in their use in written and spoken Dutch. Multivariate analyses of the frequencies with which the words were used in a factorially contrasted set of subcorpora revealed signi ficant variation involving the speaker's country, sex, and education level for spoken Dutch, and involving country and register for written Dutch. Acoustic analyses revealed that Dutch men reduced most often, while Flemish highly educated women reduced least. Two linguistic context effects emerged, one prosodic, and the other pertaining to the flow of information. Words in sentence final position showed less reduction, while words that were better predictable from the preceding word in the sentence(based on mutual information) tended to be reduced more often. The increased probability of reduction for forms that are more predictable in context, combined with the loss of the suffix in the more extremely reduced forms, suggests that highfrequency words in -lijk are undergoing a process of erosion that causes them to gravitate towards monomorphemic function words.

Abstract

This study investigates the relationship between word repetition, predictability from neighbouring words, and articulatory reduction in Dutch. For the seven most frequent words ending in the adjectival suffix -lijk, 40 occurrences were randomly selected from a large database of face-to-face conversations. Analysis of the selected tokens showed that the degree of articulatory reduction (as measured by duration and number of realized segments) was affected by repetition, predictability from the previous word and predictability from the following word. Interestingly, not all of these effects were significant across morphemes and target words. Repetition effects were limited to suffixes, while effects of predictability from the previous word were restricted to the stems of two of the seven target words. Predictability from the following word affected the stems of all target words equally, but not all suffixes. The implications of these findings for models of speech production are discussed.

Abstract

This study investigates the effects of lexical frequency on the durational reduction of morphologically complex words in spoken Dutch. The hypothesis that high-frequency words are more reduced than low-frequency words was tested by comparing the durations of affixes occurring in different carrier words. Four Dutch affixes were investigated, each occurring in a large number of words with different frequencies. The materials came from a large database of face-to-face conversations. For each word containing a target affix, one token was randomly selected for acoustic analysis. Measurements were made of the duration of the affix as a whole and the durations of the individual segments in the affix. For three of the four affixes, a higher frequency of the carrier word led to shorter realizations of the affix as a whole, individual segments in the affix, or both. Other relevant factors were the sex and age of the speaker, segmental context, and speech rate. To accommodate for these findings, models of speech production should allow word frequency to affect the acoustic realizations of lower-level units, such as individual speech sounds occurring in affixes.