Publications

Abstract

Words are fundamental to reading and yet over a century of research has not masked the controversies around how words are recognized. We review some old and new research that disproves simple ideas such as words are read as wholes or are simply mapped directly to spoken language. We also review theory and research relevant to the question of sublexical influences in word recognition. We describe orthography and phonology, how they are related to each other and describe a series of new experiments on how these sources of information are processed. Tasks include lexical decision, perceptual identification, and naming. Dependent measures are reaction time, accuracy of performance, and a new measure, initial phoneme duration, that refers to the duration of the first phoneme when the target word is pronounced. Important factors in resolving the controversies include the realization that reading has multiple determinants, as well as evaluating the type of task, proper controls such as familiarity of the test items and accuracy of measurement of the response. We also address potential limitations with measures related to the mapping between orthography and phonology, and show that the existence of a sound-to-spelling consistency effect does not require interactive activation, but can be explained and predicted by a feedforward model, the Fuzzy logical model of perception.

Abstract

Human conversations are inherently multimodal, including auditory speech, visual articulatory cues, and hand gestures. Recent studies demonstrated that the timing of a simple up-and-down hand movement, known as a beat gesture, can affect speech perception. A beat gesture falling on the first syllable of a disyllabic word induces a bias to perceive a strong-weak stress pattern (i.e., “CONtent”), while a beat gesture falling on the second syllable combined with the same acoustics biases towards a weak-strong stress pattern (“conTENT”). This effect, termed the “manual McGurk effect”, has been studied in both in-lab and online studies, employing standard experimental sessions lasting approximately forty minutes. The present work tests whether the manual McGurk effect can be observed in an online short version (“mini-test”) of the original paradigm, lasting only ten minutes. Additionally, we employ two different response modalities, namely a two-alternative forced choice and a visual analog scale. A significant manual McGurk effect was observed with both response modalities. Overall, the present study demonstrates the feasibility of employing a ten-minute manual McGurk mini-test to obtain a measure of gesture-speech integration. As such, it may lend itself for inclusion in large-scale test batteries that aim to quantify individual variation in language processing.

Abstract

With the recent advancements in the field of robotics and the increased focus on having general-purpose robots widely available to the general public, it has become increasingly necessary to pursue research into Human-robot interaction (HRI). While there have been a lot of works discussing frameworks for teaching HRI in educational institutions with a few institutions already offering courses to students, a consensus on the course content still eludes the field. In this work, we highlight a few challenges and opportunities while designing an HRI course from an Indian perspective. These topics warrant further deliberations as they have a direct impact on the design of HRI courses and wider implications for the entire field.

Abstract

Natural speech involves repair. These repairs are often highlighted through prosodic marking (Levelt & Cutler, 1983). Prosodic marking usually entails an increase in pitch, loudness, and/or duration that draws attention to the corrected word. While it is established that natural self-repairs typically elicit prosodic marking, the exact cause of this is unclear. This study investigates whether producing a prosodic marking emerges from an automatic correction process or has a communicative purpose. In the current study, we elicit corrections to test whether all self-corrections elicit prosodic marking. Participants carried out a picture-naming task in which they described two images presented on-screen. To prompt self-correction, the second image was altered in some cases, requiring participants to abandon their initial utterance and correct their description to match the new image. This manipulation was compared to a control condition in which only the orientation of the object would change, eliciting no self-correction while still presenting a visual change. We found that the replacement of the item did not elicit a prosodic marking, regardless of the type of change. Theoretical implications and research directions are discussed, in particular theories of prosodic planning.

Abstract

Recent FMRI studies indicate that language related brain regions are engaged in artificial grammar (AG) processing. In the present study we investigate the Reber grammar by means of formal analysis and network simulations. We outline a new method for describing the network dynamics and propose an approach to grammar extraction based on the state-space dynamics of the network. We conclude that statistical frequency-based and rule-based acquisition procedures can be viewed as complementary perspectives on grammar learning, and more generally, that classical cognitive models can be viewed as a special case of a dynamical systems perspective on information processing

Abstract

It has been shown that when speakers produce hand gestures, addressees are attentive towards these gestures, using them to facilitate speech processing. Even relatively simple “beat” gestures are taken into account to help process aspects of speech such as prosodic prominence. In fact, recent evidence suggests that the timing of a beat gesture can influence spoken word recognition. Termed the manual McGurk Effect, Dutch participants, when presented with lexical stress minimal pair continua in Dutch, were biased to hear lexical stress on the syllable that coincided with a beat gesture. However, little is known about how this manual McGurk effect would surface in languages other than Dutch, with different acoustic cues to prominence, and variable gestures. Therefore, this study tests the effect in Spanish where lexical stress is arguably even more important, being a contrastive cue in the regular verb conjugation system. Results from 24 participants corroborate the effect in Spanish, namely that when given the same auditory stimulus, participants were biased to perceive lexical stress on the syllable that visually co-occurred with a beat gesture. These findings extend the manual McGurk effect to a different language, emphasizing the impact of gestures' timing on prosody perception and spoken word recognition.

Abstract

Recent research on multimodal language production has revealed that prominence in speech and gesture go hand-in-hand. Specifically, peaks in gesture (i.e., the apex) seem to closely coordinate with peaks in fundamental frequency (F0). The nature of this relationship may also be bi-directional, as it has also been shown that the production of gesture directly affects speech acoustics. However, most studies on the topic have largely focused on stress-based languages, where fundamental frequency has a prominence-lending function. Less work has been carried out on lexical tone languages such as Mandarin, where F0 is lexically distinctive. In this study, four native Mandarin speakers were asked to produce single monosyllabic CV words, taken from minimal lexical tone triplets (e.g., /pi1/, /pi2/, /pi3/), either with or without a beat gesture. Our analyses of the timing of the gestures showed that the gesture apex most stably occurred near vowel onset, with consonantal duration being the strongest predictor of apex placement. Acoustic analyses revealed that words produced with gesture showed raised F0 contours, greater intensity, and shorter durations. These findings further our understanding of gesture-speech alignment in typologically diverse languages, and add to the discussion about multimodal prominence.

Abstract

We investigated the relationship between visual experience and pragmatic development by testing the socio-communicative skills of a unique population: the Prakash children of India, who received treatment for congenital cataracts after years of visual deprivation. Using two different referential communication tasks, our study investigated Prakash' children ability to produce sufficiently informative referential expressions (e.g., ‘the green pear' or ‘the small plate') and pay attention to their interlocutor's face during the task (Experiment 1), as well as their ability to recognize a speaker's referential intent through non-verbal cues such as head turning and pointing (Experiment 2). Our results show that Prakash children have strong pragmatic skills, but do not look at their interlocutor's face as often as neurotypical children do. However, longitudinal analyses revealed an increase in face fixations, suggesting that over time, Prakash children come to utilize their improved visual skills for efficient referential communication.

Abstract

Despite decades of study, we still know less than we would like about the association between joint attention (JA) and language acquisition. This is partly because of disagreements on how to operationalise JA. In this study, we examine the impact of applying two different, influential JA operationalisation schemes to the same dataset of child-caregiver interactions, to determine which yields a better fit to children's later vocabulary size. Two coding schemes— one defining JA in terms of gaze overlap and one in terms of social aspects of shared attention—were applied to video-recordings of dyadic naturalistic toy-play interactions (N=45). We found that JA was predictive of later production vocabulary when operationalised as shared focus (study 1), but also that its operationalisation as shared social awareness increased its predictive power (study 2). Our results emphasise the critical role of methodological choices in understanding how and why JA is associated with vocabulary size.

Abstract

A series of experiment tested Ekman’s (1992) hypothesis that there are a set of positive basic emotions that are expressed using vocal para-linguistic sounds, e.g. laughter and cheers. The proposed categories investigated were amusement, contentment, pleasure, relief and triumph. Behavioural testing using a forced-choice task indicated that participants were able to reliably recognize vocal expressions of the proposed emotions. A cross-cultural study in the preliterate Himba culture in Namibia confirmed that these categories are also recognized across cultures. A recognition test of acoustically manipulated emotional vocalizations established that the recognition of different emotions utilizes different vocal cues, and that these in turn differ from the cues used when comprehending speech. In a study using fMRI we found that relative to a signal correlated noise baseline, the paralinguistic expressions of emotion activated bilateral superior temporal gyri and sulci, lateral and anterior to primary auditory cortex, which is consistent with the processing of non linguistic vocal cues in the auditory ‘what’ pathway. Notably amusement was associated with greater activation extending into both temporal poles and amygdale and insular cortex. Overall, these results support the claim that ‘happiness’ can be fractionated into amusement, pleasure, relief and triumph.

Abstract

This paper addresses the issue of large-vocabulary recognition in a specific word class. We propose a two-pass strategy in which only major cities are explicitly represented in the first stage lexicon. An unknown word model encoded as a phone loop is used to detect OOV city names (referred to as rare city names). After which SpeM, a tool that can extract words and word-initial cohorts from phone graphs on the basis of a large fallback lexicon, provides an N-best list of promising city names on the basis of the phone sequences generated in the first stage. This N-best list is then inserted into the second stage lexicon for a subsequent recognition pass. Experiments were conducted on a set of spontaneous telephone-quality utterances each containing one rare city name. We tested the size of the N-best list and three types of language models (LMs). The experiments showed that SpeM was able to include nearly 85% of the correct city names into an N-best list of 3000 city names when a unigram LM, which also boosted the unigram scores of a city name in a given state, was used.

Abstract

In this paper, we illustrate the close parallels between the research fields of human speech recognition (HSR) and automatic speech recognition (ASR) using a computational model of human word recognition, SpeM, which was built using techniques from ASR. We show that ASR has proven to be useful for improving models of HSR by relieving them of some of their shortcomings. However, in order to build an integrated computational model of all aspects of HSR, a lot of issues remain to be resolved. In this process, ASR algorithms and techniques definitely can play an important role.

Abstract

A corpus of digitized speech errors is used to compare the prosody of correction patterns for word-level vs. sound-level errors. Results for both peak F0 and perceived prosodic markedness confirm that speakers are more likely to mark corrections of word-level errors than corrections of sound-level errors, and that errors ambiguous between word-level and soundlevel (such as boat for moat) show correction patterns like those for sound level errors. This finding increases the plausibility of the claim that word-sound-ambiguous errors arise at the same level of processing as sound errors that do not form words.

Abstract

This paper investigates the interaction between acoustic scores and symbolic mismatch penalties in multi-pass speech decoding techniques that are based on the creation of a segment graph followed by a lexical search. The interaction between acoustic and symbolic mismatches determines to a large extent the structure of the search space of these multipass approaches. The background of this study is a recently developed computational model of human word recognition, called SpeM. SpeM is able to simulate human word recognition data and is built as a multi-pass speech decoder. Here, we focus on unravelling the structure of the search space that is used in SpeM and similar decoding strategies. Finally, we elaborate on the close relation between distances in this search space, and distance measures in search spaces that are based on a combination of acoustic and phonetic features.

Abstract

The human brain deals with the infinite variability of speech through multiple mechanisms. Some of them rely solely on information in the speech input (i.e., signal-driven) whereas some rely on linguistic or real-world knowledge (i.e., knowledge-driven). Many signal-driven perceptual processes rely on the enhancement of acoustic differences between incoming speech sounds, producing contrastive adjustments. For instance, when an ambiguous voiceless fricative is preceded by a high fundamental frequency (f0) sentence, the fricative is perceived as having lower a spectral center of gravity (CoG). However, it is not clear whether knowledge of a talker’s typical f0 can lead to similar contrastive effects. This study investigated a possible talker f0 effect on fricative CoG perception. In the exposure phase, two groups of participants (N=16 each) heard the same talker at high or low f0 for 20 minutes. Later, in the test phase, participants rated fixed-f0 /?ɔk/ tokens as being /sɔk/ (i.e., high CoG) or /ʃɔk/ (i.e., low CoG), where /?/ represents a fricative from a 5-step /s/-/ʃ/ continuum. Surprisingly, the data revealed the opposite of our contrastive hypothesis, whereby hearing high f0 instead biased perception towards high CoG. Thus, we demonstrated that talker f0 information affects fricative CoG perception.

Abstract

Contrastive pitch accents can mark sentence elements occupying parallel roles. In “Mary kissed John, not Peter”, a pitch accent on Mary or John cues the implied syntactic role of Peter. Van der Burght, Friederici, Goucha, and Hartwigsen (2021) showed that listeners can build expectations concerning syntactic and semantic properties of upcoming words, derived from pitch accent information they heard previously. To further explore these expectations, we attempted a partial replication of the original German study in Dutch. In the experimental sentences “Yesterday, the police officer arrested the thief, not the inspector/murderer”, a pitch accent on subject or object cued the subject/object role of the ellipsis clause. Contrasting elements were additionally cued by the thematic role typicality of the nouns. Participants listened to sentences in which the ellipsis clause was omitted and selected the most plausible sentence-final noun (presented visually) via button press. Replicating the original study results, listeners based their sentence-final preference on the pitch accent information available in the sentence. However, as in the original study, individual differences between listeners were found, with some following prosodic information and others relying on a structural bias. The results complement the literature on ellipsis resolution and on interindividual variability in cue weighting.

Abstract

Tzeltal, a Mayan language spoken in southern Mexico, exhibits allo-morphy of an unusual type. The vowel quality of the perfective suffix is determined by the number of syllables in the stem to which it is attaching. This paper presents previously unpublished data of this allomorphy and demonstrates that a syllable-count analysis of the phenomenon is the proper one. This finding is put in a more general context of segment-prosody interaction in allomorphy.

Abstract

How do languages express ideas of movement, and how do they package features that can be part of motion, such as path and cause? This questionnaire is used to gain a picture of the lexical resources a language draws on for motion expressions. It targets issues of semantic conflation (i.e., what other semantic information besides motion may be encoded in a verb root) and patterns of semantic distribution (i.e., what types of information are encoded in the morphemes that come together to build a description of a motion event). It was originally designed for Australian languages, but has since been used around the world.

Abstract

Contrastive reference, where a speaker presents or identifies one item in explicit contrast to another (I like this book but that one is boring), has special communicative and information structure properties. This can be reflected in rules of demonstrative use. For example, in some languages, terms equivalent to this and that can be used for contrastive reference in almost any spatial context. But other two-term languages stick more closely to “distance rules” for demonstratives, allowing a this-like term in close space only. This task elicits data concerning one context of contrastive reference, focusing on whether (and how) non-proximal demonstratives can be used to distinguish objects within a proximal area. The task runs like a memory game, with the consultant being asked to identify the locations of two or three hidden items arranged within arm’s reach.

Abstract

Demonstrative terms (e.g., this and that) are key to understanding how a language constructs and interprets spatial relationships. They are tricky to pin down, typically having functions that do not match “idealized” uses, and that can become invisible in narrow elicitation settings. This questionnaire is designed to identify the range(s) of use of certain spatial demonstrative terms, and help assess the roles played by gesture, access, attention, and addressee knowledge in demonstrative use. The stimuli consist of 25 diagrammed “elicitation settings” to be created by the researcher.

Abstract

Angelika Wittek untersuchte Zustandsveränderungsverben bei vier- bis sechsjährigen Kindern. Englischsprechende Kinder verstehen bis zum Alter von 8 Jahren diese Verben als Bewegungsverben und ignorieren, daß sie zusätzlich die Information über einen Endzustand im Sinne der Negation des Ausgangszustands beeinhalten. Wittek zeigte, daß entgegen der Erwartung transparente, morphologisch komplexe Formen (wachmachen), in denen die Partikel den Endzustand explizit macht, nicht besser verstanden werden als Simplizia (wecken). Zudem diskutierte sie, inwieweit die Verwendung des Adverbs wieder in restitutiver Lesart Hinweise auf den Erwerb dieser Verben geben kann.

Abstract

Early word learning involves mapping individual words to their meanings and building organized semantic representations among words. Previous corpus-based studies (e.g., using text from websites, newspapers, child-directed speech corpora) demonstrated that linguistic information such as word co-occurrence alone is sufficient to build semantically organized word knowledge. The present study explored two new research directions to advance understanding of how infants acquire semantically organized word knowledge. First, infants in the real world hear words surrounded by contextual information. Going beyond inferring semantic knowledge merely from language input, we examined the role of extra-linguistic contextual information in learning semantic knowledge. Second, previous research relies on large amounts of linguistic data to demonstrate in-principle learning, which is unrealistic compared with the input children receive. Here, we showed that incorporating extra-linguistic information provides an efficient mechanism through which semantic knowledge can be acquired with a small amount of data infants perceive in everyday learning contexts, such as toy play.

Abstract

Prosodic prominence can enhance memory for the prominent words. This mnemonic benefit has been linked to listeners’ allocation of attention and deeper processing, which leads to more robust semantic representations. We investigated whether, in addition to the well-established effect at the semantic level, there was a memory benefit for prominent words at the phonological level. To do so, participants (48 native speakers of Dutch), first performed an accent judgement task, where they had to discriminate accented from unaccented words, and accented from unaccented pseudowords. All stimuli were presented in lists. They then performed an old/new recognition task for the stimuli. Accuracy in the accent judgement task was equally high for words and pseudowords. In the recognition task, performance was, as expected, better for words than pseudowords. More importantly, there was an interaction of accent with word type, with a significant advantage for accented compared to unaccented words, but not for pseudowords. The results confirm the memory benefit for accented compared to unaccented words seen in earlier studies, and they are consistent with the view that prominence primarily affects the semantic encoding of words. There was no evidence for an additional memory benefit arising at the phonological level.

Abstract

In Swedish, words are associated with either of two pitch contours known as Accent 1 and Accent 2. Using a psychometric test, we investigated how listeners judge pitch accent violations while interpreting discourse. Forty native speakers of Central Swedish were presented with auditory dialogues, where test words were appropriately or inappropriately accented in a given context, and asked to judge the correctness of sentences containing the test words. Data indicated a statistically significant effect of wrong accent pattern on the correctness judgment. Both Accent 1 and Accent 2 violations interfered with the coherent interpretation of discourse and were judged as incorrect by the listeners. Moreover, there was a statistically significant difference in the perceived correctness between the accent patterns. Accent 2 violations led to a lower correctness score compared to Accent 1 violations, indicating that the listeners were more sensitive to pitch accent violations in Accent 2 words than in Accent 1 words. This result is in line with the notion that Accent 2 is marked and lexically represented in Central Swedish. Taken together, these findings indicate that listeners use both Accent 1 and Accent 2 to arrive at the correct interpretation of the linguistic input, while assigning varying degrees of relevance to them depending on their markedness.