Presentations

Abstract

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Abstract

Speaking requires translating concepts into a sequence of sounds. Contemporary models of language production assume that this translation involves a series of steps: from selecting the concepts to be expressed, to phonetic and articulatory encoding of the words. In addition, speakers monitor their planned output using sensorimotor predictive mechanisms. The current work concerns phonetic encoding and the speaker's monitoring of articulation. Specifically, we test whether monitoring is sensitive to the frequency of syllable-sized representations.
We run a series of immediate and delayed syllable production experiments (repetition and reading). We exploit the syllable-frequency effect: in immediate naming, high-frequency syllables are produced faster than low-frequency syllables. The effect is thought to reflect the stronger automatization of motor plan retrieval of high-frequency syllables during phonetic encoding. We predict distinct ERP and spatiotemporal patterns for high- vs. low-frequency syllables. Following articulation, we analyse auditory-evoked N1 responses that – among other features – reflect the suppression of one's own speech. Low-frequency syllables are expected to require more close monitoring, and therefore smaller N1/P2 amplitudes. The results can be important as effects of syllable frequency stand to inform us about the tradeoff between stored versus assembled representations for setting sensory targets in the production of speech.

Abstract

Speaking requires translating concepts into a sequence of sounds. Contemporary models of language production assume that this translation involves a series of steps: from selecting the concepts to be expressed, to phonetic and articulatory encoding of the words. In addition, speakers monitor their planned output using sensorimotor predictive mechanisms. The current work concerns phonetic encoding and the speaker's monitoring of articulation. Specifically, we test whether monitoring is sensitive to the frequency of syllable-sized representations.
We run a series of immediate and delayed syllable production experiments (repetition and reading). We exploit the syllable-frequency effect: in immediate naming, high-frequency syllables are produced faster than low-frequency syllables. The effect is thought to reflect the stronger automatization of motor plan retrieval of high-frequency syllables during phonetic encoding. We predict distinct ERP and spatiotemporal patterns for high- vs. low-frequency syllables. Following articulation, we analyse auditory-evoked N1 responses that – among other features – reflect the suppression of one's own speech. Low-frequency syllables are expected to require more close monitoring, and therefore smaller N1/P2 amplitudes. The results can be important as effects of syllable frequency stand to inform us about the tradeoff between stored versus assembled representations for setting sensory targets in the production of speech.

Abstract

Producing spontaneous speech is challenging. It often contains disfluencies like repetitions, prolongations, silent pauses or filled pauses. Previous research has largely focused on the language-based factors (e.g., planning difficulties) underlying the production of these disfluencies. But research has also shown that some speakers are more disfluent than others. What cognitive mechanisms underlie this difference? We reanalyzed a behavioural dataset of 112 participants, who were assessed on a battery of tasks testing linguistic knowledge, processing speed, non-verbal IQ, working memory, and basic production skills and also produced six 1-minute samples of spontaneous speech (Hintz et al., 2020). We assessed the length and lexical diversity of participants’ speech and determined how often they produced silent pauses and filled pauses. We used network analysis, factor analysis and non-parametric regressions to investigate the relationship between these variables and individual differences in particular cognitive skills. We found that individual differences in linguistic knowledge or processing speed were not related to the production of disfluencies. In contrast, the proportion of filled pauses (relative to all words in the 1-minute narratives) correlated negatively with working memory capacity.

Abstract

Convergence broadly refers to interlocutors’ tendency to progressively sound more like each other over time. Recent empirical work has used various experimental paradigms to observe convergence in voice fundamental frequency (f0). One study used stable mean f0 over trials in a synchronous speech task with manipulated (i.e., high and low) f0 conditions (Bradshaw & McGettigan, 2021). Here, we attempted to replicate this study in Dutch. First, in a reading task, participants read 40 sentences at their own pace to establish f0 baselines. Later, in a synchronous speech task, participants read 80 sentences in synchrony with a speaker whose voice was manipulated ±2st above or below (i.e., for the high and low f0 conditions, respectively) a reference mean f0 value. The reference mean f0 value and the manipulation size were obtained across multiple pre-tests. Our results revealed that the f0 manipulation significantly predicted f0 convergence in both high f0 and low f0 conditions. Furthermore, the proportion of convergers in the sample was larger than those reported by Bradshaw & McGettigan, highlighting the benefits of stimulus optimization. Our study thus provides stronger evidence that the pitch of two talkers tends to converge as they speak together.

Abstract

The semantic interference effect in picture naming entails longer naming latencies for pictures presented with semantically related versus unrelated distractors. One factor suggested to influence the effect is word category. However, results have been inconclusive. Momma et al. (2020) used a sentence-picture interference paradigm where the sentence context (“her singing” or “she’s singing”) disambiguated the word category (noun or verb, respectively) of distractor and target, manipulating their word category match/mismatch. Semantic interference was only found when distractor and target belonged to the same word category, suggesting that syntactic category constrains lexical competition during sentence production. Considering this important theoretical conclusion, we conducted a preregistered replication study with Dutch participants, mirroring the design of the original study. In each of 2 experiments, 60 native speakers read sentences containing sentence-final distractor words that had to be interpreted as nouns or verbs, depending on the sentence context. Subsequently, they named target action pictures as either verbs (experiment 1) or nouns (experiment 2). Results of Experiment 1 showed a main effect of relatedness, suggesting a semantic interference effect regardless of word category. We discuss differences between the original and current study results with cross-linguistic differences in (de)compositional processing and frequency of distractor forms.

Abstract

When we communicate, we often use language to identify and successfully transmit new information. We can highlight new and important information by focussing it through pitch, syntactic structure, or semantic content. Previous work has shown that focussed information is remembered better than neutral or unfocussed information. However, most of this work has used structures, like clefts and pseudo-clefts, that are rarely found in communication. We used spoken question-answer pairs, a frequent structure where the answers are focussed relative to the questions, to examine whether answers are remembered better than questions. On each trial, participants (n=48) saw three pictures on the screen while listening to a recorded question-answer exchange between two people, such as “What should move under the crab? – The sunflower!”. In an online Yes/No recognition memory test on the next day, participants recognised the names of pictures that appeared as answers 6% more accurately than the names of pictures that appeared as questions (β = 0.27, Wald z = 4.51, 95% CI = 0.15, 0.39, p = < 0.001). Thus, linguistic focus affected memory for the words of an overheard conversation. We discuss the methodological and theoretical implications of the findings for studies of conversation.

Abstract

It is evident that speakers can freely vary stylistic features of their speech, such as speech rate, but how they accomplish this has hardly been studied, let alone implemented in a formal model of speech production. Much as in walking and running, where qualitatively different gaits are required cover the gamut of different speeds, we might predict there to be multiple qualitatively distinct configurations, or ‘gaits’, in the speech planning system that speakers must switch between to alter their speaking rate or style. Alternatively, control might involve continuous modulation of a single ‘gait’. We investigate these possibilities by simulation of a connectionist computational model which mimics the temporal characteristics of observed speech. Different ‘regimes’ (combinations of parameter settings) can be engaged to achieve different speaking rates.

The model was trained separately for each speaking rate, by an evolutionary optimisation algorithm. The training identified parameter values that resulted in the model to best approximate syllable duration distributions characteristic of each speaking rate.

In one gait system, the regimes used to achieve fast and slow speech are qualitatively similar, but quantitatively different. In parameter space, they would be arranged along a straight line. Different points along this axis correspond to different speaking rates. In a multiple gait system, this linearity would be missing. Instead, the arrangement of the regimes would be triangular, with no obvious relationship between the regions associated with each gait, and an abrupt shift in parameter values to move from speeds associated with ‘walk-speaking’ to ‘run-speaking’.

Our model achieved good fits in all three speaking rates. In parameter space, the arrangement of the parameter settings selected for the different speaking rates is non-axial, suggesting that ‘gaits’ are present in the speech planning system.

Abstract

It is unknown whether modality affects the efficiency with which humans learn novel word forms and their meanings, with previous studies reporting both written and auditory advantages. The current study implements controls whose absence in previous work likely offers explanation for such contradictory findings. In two novel word learning experiments, participants were trained and tested on pseudoword - novel object pairs, with controls on: modality of test, modality of meaning, duration of exposure and transparency of word form. In both experiments word forms were presented in either their written or spoken form, each paired with a pictorial meaning (novel object). Following a 20-minute filler task, participants were tested on their ability to identify the picture-word form pairs on which they were trained. A between subjects design generated four participant groups per experiment 1) written training, written test; 2) written training, spoken test; 3) spoken training, written test; 4) spoken training, spoken test. In Experiment 1 the written stimulus was presented for a time period equal to the duration of the spoken form. Results showed that when the duration of exposure was equal, participants displayed a written training benefit. Given words can be read faster than the time taken for the spoken form to unfold, in Experiment 2 the written form was presented for 300 ms, sufficient time to read the word yet 65% shorter than the duration of the spoken form. No modality effect was observed under these conditions, when exposure to the word form was equivalent. These results demonstrate, at least for proficient readers, that when exposure to the word form is controlled across modalities the efficiency with which word form-meaning associations are learnt does not differ. Our results therefore suggest that, although we typically begin as aural-only word learners, we ultimately converge on developing learning mechanisms that learn equally efficiently from both written and spoken materials.

Abstract

Studies on the generation effect have found that coming up with words, compared to reading them, improves memory. However, because these studies used words at both study and test, it is unclear whether generation affects visual or conceptual/lexical representations. Here, participants named pictures after hearing the picture name (no-generation condition), backward speech, or an unrelated word (easy and harder generation conditions). We ruled out effects at the visual level by testing participants’ recognition memory on the written names of the pictures that were named earlier. We also assessed the effect of processing time during generation on memory. In the recognition memory test, participants were more accurate in the generation conditions than in the no-generation condition. They were also more accurate for words that took longer to be retrieved, but only when generation was required. This work shows that generation affects conceptual/lexical representations and informs the relationship between language and memory.

Abstract

Interlocutors perceive phonemic category boundaries relative to talkers’ produced speech rates. For instance, a temporally ambiguous vowel between Dutch short /A/ and long /a:/ sounds short (i.e., as /A/) in a slow speech context, but long in a fast context. Besides the local contextual speech rate, listeners also track talker-specific habitual speech rates (Maslowski et al., in press). However, it is yet unclear whether self-produced speech rate modulates perception of another talker’s habitual rate. Such effects are potentially important, given that, in dialogue, a listener’s own speech often constitutes the context for the interlocutor’s speech. Three experiments addressed this question. In Experiment 1, one group of participants was instructed to speak fast, whereas another group had to speak slowly (16 participants per group). The two groups were then compared on their perception of ambiguous Dutch /A/-/a:/ vowels embedded in neutral rate speech from another talker. In Experiment 2, the same participants listened to playback of their own speech, whilst evaluating target vowels in neutral rate speech as before. Neither of these experiments provided support for the involvement of self-produced speech in perception of another talker's speech rate. Experiment 3 repeated Experiment 2 with a new participant sample, who were unfamiliar with the participants from the previous two experiments. Here, a group effect was found on perception of the neutral rate talker. This result replicates the finding of Maslowski et al. that habitual speech rates are perceived relative to each other (i.e., neutral rate sounds fast in the presence of a slower talker and vice versa), with naturally produced speech. Taken together, the findings show that self-produced speech is processed differently from speech produced by others. They carry implications for our understanding of the link between production and perception in dialogue.

Abstract

That speakers can vary their speaking rate is evident, but how they accomplish this has
hardly been studied. The effortful experience of deviating from one's preferred speaking rate
might result from shifting between different regimes (system configurations) of the speech
planning system. This study investigates control over speech rate through simulations of a
new connectionist computational model of the cognitive process of speech production, derived
from Dell, Burger and Svec’s (1997) model to fit the temporal characteristics of observed
speech. We draw an analogy from human movement: the selection of walking and running
gaits to achieve different movement speeds. Are the regimes of the speech production system
arranged into multiple ‘gaits’ that resemble walking and running?
During training of the model, different parameter settings are identified for different speech
rates, which can be conflated with the regimes of the speech production system. The
parameters can be considered to be dimensions of a high-dimensional ‘regime space’, in
which different regimes occupy different parts of the space.
In a single gait system, the regimes are qualitatively similar, but quantitatively different.
They are arranged along a straight line through regime space. Different points along this axis
correspond directly to different speaking rates. In a multiple gait system, the arrangement of
the regimes is more disperse, with no obvious relationship between the regions associated
with each gait.
After training, the model achieved good fits in all three speaking rates, and the parameter
settings associated with each speaking rate were different. The broad arrangement of the
parameter settings for the different speaking rates in regime space was non-axial, suggesting
that ‘gaits’ may be present in the speech planning system.

Abstract

In recent years, the theory that prediction is an important part of language processing has gained considerable attention (see Huettig, 2015, for overview). There is a large body of empirical evidence which suggests that language users’ ability to anticipate interlocutors’ upcoming utterances is one of the reasons why interactive speech can be so effortless, smooth, and efficient in nature (e.g. Wicha et al., 2004; van Berkum et al., 2005). The present study aimed to investigate whether the language production module is affected by prediction of another individual’s utterances using a joint language production task designed to establish whether simulation of an interlocutor’s utterance occurs automatically, even if this hinders one’s own speech production. The experiment aimed to replicate the finding of an interference effect in a joint naming task (Gambi et al., 2015), and investigate whether the same patterns could be found within a clearer social context where a partner was co-present in the same room. Participants named pictures of objects while their partners concurrently named or categorised congruent or incongruent stimuli. Analyses of naming onset latencies indicate that individuals may partially co-represent their partner’s utterances and that this shared representation influences language production. Congruency in task and stimuli display facilitated naming compared to incongruent trials which showed a tendency to impede production latencies. This finding of a social effect in a setting where simulation of language content is not necessary may suggest that some kind of anticipatory processing is an underlying feature of comprehension.

Abstract

Previous work on memory phenomena shows that pictures and words lead to a production effect, i.e. better memory for aloud than silent items, and that this interacts with the picture superiority effect, i.e. better memory for pictures than words (Fawcett, Quinlan and Taylor, 2012). We investigated the role of the generation effect, i.e. improved memory for generated words, in picture naming. As picture naming requires participants to think of an appropriate label, a generation effect might be elicited for pictures but not words. Forty-two participants named pictures silently or aloud and were given the correct picture name or an unreadable label; all conditions included pictures to control for the picture superiority effect. Memory was then tested using a yes/no recognition task. We found a production effect (p < 0.001) showing the role of articulation in memory, a generation effect (p < 0.001) showing the role of lexical access in memory, and an interaction (p <0.05) between the two suggesting the non-independence of the effects. Ongoing work further tests the role of label reliability in eliciting these effects. This research demonstrates a role for the generation effect in picture naming, with implications for memory asymmetries at different stages in language production.

Abstract

Conversation often involves simultaneous production and comprehension, yet little research has investigated whether these two processes interfere with one another. We tested participants’ ability to dual-task with production and comprehension tasks. Task one (production task) was picture naming. Task two (comprehension task) was either syllable identification (linguistic condition) or tone identification (non-linguistic condition). The two identification tasks were matched for difficulty. Three SOAs (50ms, 300ms, and 1800ms) resulted in different amounts of overlap between the production and comprehension tasks. We hypothesized that as production and comprehension use similar resources there would be greater interference with concurrent linguistic than non-linguistic tasks.
At the 50ms SOA, picture naming latencies were slower in the linguistic compared to the non-linguistic condition, suggesting that the resources required for production and comprehension overlap more in the linguistic condition. As the syllables were non-words without lexical representations, this interference likely occurs primarily at the phonological level. Across all SOAs, identification RTs were longer in the linguistic condition, showing that such phonological interference percolates through to the comprehension task, regardless of SOA. In sum, these results demonstrate that concurrent access to the phonological level in production and comprehension results in measurable interference in both speaking and comprehending.

Abstract

Speech rate is known to modulate perception of temporally ambiguous speech sounds. For instance, a vowel may be perceived as short when the immediate speech context is slow, but as long when the context is fast. Yet, effects of long-term tracking of speech rate are largely unexplored. Two experiments tested whether long-term tracking of rate influences perception of the temporal Dutch vowel contrast /A/-/a:/. In Experiment 1, one low-rate group listened to ‘neutral’ rate speech from talker A and to slow speech from talker B. Another high-rate group was exposed to the same neutral speech from A, but to fast speech from B. Between-group comparison of the ‘neutral’ trials revealed that the low-rate group reported a higher proportion of /a:/ in A’s ‘neutral’ speech, indicating that A sounded faster when B was slow. Experiment 2 tested whether one’s own speech rate also contributes to effects of long-term tracking of rate. Here, talker B’s speech was replaced by playback of participants’ own fast or slow speech. No evidence was found that one’s own voice affected perception of talker A in larger speech contexts. These results carry implications for our understanding of the mechanisms involved in rate-dependent speech perception and of dialogue.

Abstract

Speech rate is known to modulate perception of temporally ambiguous speech sounds. For instance, a vowel may be perceived as short when the immediate speech context is slow, but as long when the context is fast. Yet, effects of long-term tracking of speech rate are largely unexplored. Two experiments tested whether long-term tracking of rate influences perception of the temporal Dutch vowel contrast /ɑ/-/a:/. In Experiment 1, one low-rate group listened to 'neutral' rate speech from talker A and to slow speech from talker B. Another high-rate group was exposed to the same neutral speech from A, but to fast speech from B. Between-group comparison of the 'neutral' trials revealed that the low-rate group reported a higher proportion of /a:/ in A's 'neutral' speech, indicating that A sounded faster when B was slow. Experiment 2 tested whether one's own speech rate also contributes to effects of long-term tracking of rate. Here, talker B's speech was replaced by playback of participants' own fast or slow speech. No evidence was found that one's own voice affected perception of talker A in larger speech contexts. These results carry implications for our understanding of the mechanisms involved in rate-dependent speech perception and of dialogue.

Abstract

Speech can be produced at different rates. The ability to produce faster or slower speech may be thought to result from executive control processes enlisted to modulate lexical selection and phonological encoding stages of speech planning.

This study used simulations of the model of serial order in language by Dell, Burger and Svec (1997, DBS) to characterise the strategies adopted by speakers when naming pictures at fast, medium and slow prescribed rates. Our new implementation of DBS was able to produce activation patterns that correlated strongly with observed syllable-level timing of disyllabic words from this task.

For each participant, different speaking rates were associated with different regions of the DBS parameter space. The precise placement of the speaking rates in the parameter space differed markedly between participants. Participants applied broadly the same parameter manipulation to accelerate their speech. This was however not the case for deceleration. Hierarchical clustering revealed two distinct patterns of parameter adjustment employed to decelerate speech, suggesting that deceleration is not necessarily achieved by the inverse process of acceleration. In addition, potential refinements to the DBS model are discussed.