Phonetic Perception Research Articles

Individual differences in the consistency of neural and behavioural responses to speech sounds

There are documented individual differences among adults in the consistency of speech sound processing, both at neural and behavioural levels. Some adults show more consistent neural responses to speech sounds than others, as measured by an event-related potential called the frequency-following response (FFR); similarly, some adults show more consistent behavioural responses to native speech sounds than others, as measured by two-alternative forced choice (2AFC) and visual analog scaling (VAS) tasks. Adults also differ in how successfully they can perceive non-native speech sounds. Interestingly, it remains unclear whether these differences are related within individuals. In the current study, native English-speaking adults completed native phonetic perception tasks (2AFC and VAS), a non-native (German) phonetic perception task, and an FFR recording session. From these tasks, we derived measures of the consistency of participants’ neural and behavioural responses to native speech as well as their non-native perception ability. We then examined the relationships among individual differences in these measures. Analysis of the behavioural measures revealed that more consistent responses to native sounds predicted more successful perception of unfamiliar German sounds. Analysis of neural and behavioural data did not reveal clear relationships between FFR consistency and our phonetic perception measures. This multimodal work furthers our understanding of individual differences in speech processing among adults, and may eventually lead to individualized approaches for enhancing non-native language acquisition in adulthood.

Exploring individual differences in native phonetic perception and their link to nonnative phonetic perception.

Adults differ considerably in their perception of both native and nonnative phonemes. For instance, when presented with continua of native phonemes on two-alternative forced choice (2AFC) or visual analog scaling (VAS) tasks, some people show sudden changes in responses (i.e., steep identification slopes) and others show gradual changes (i.e., shallow identification slopes). Moreover, some adults are more successful than others at learning unfamiliar phonemes. The predictors of these individual differences and the relationships between them are poorly understood. It also remains unclear to what extent different tasks (2AFC vs. VAS) may reflect distinct individual differences in perception. In two experiments, we addressed these questions by examining the relationships between individual differences in performance on native and nonnative phonetic perception tasks. We found that shallow 2AFC identification slopes were not related to shallow VAS identification slopes but were related to inconsistent VAS responses. Additionally, our results suggest that consistent native perception may play a role in promoting successful nonnative perception. These findings help characterize the nature of individual differences in phonetic perception and contribute to our understanding of how to measure such differences. This work also has implications for encouraging successful acquisition of new languages in adulthood. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Supplemental Material for Exploring Individual Differences in Native Phonetic Perception and Their Link to Nonnative Phonetic Perception

Supplemental Material for Exploring Individual Differences in Native Phonetic Perception and Their Link to Nonnative Phonetic Perception

Outline of the problem of developing the phonetic level of speech in older preschool children with logopathology

The scientific article presents the theoretical position of modern research on the content of the phonetic level of speech. Attention has been focused on the problem of studying the components of the phonetic level of speech in older preschool children with normotypical psychophysical development and speech disorders. The phonetic level of speech in children with logopathology was experimentally investigated and a comparative analysis was carried out with peers with normotypical psychophysical development. The purpose of the study is to study the current state of formation of the phonetic level of speech in older preschool children with speech pathology. The task of the research: scientific and theoretical substantiation of scientific positions regarding the development of the phonemic level of speech in children with normotypical psychophysical development and outlining the features of its development in children with logopathology; definition of tasks and evaluation criteria for studying the phonemic level of speech; carrying out a comparative analysis of the results of the study of the state of formation on the development of the phonemic level of speech in children of older preschool age with normotypical psychophysical development and with logopathology. The methods of research are tasks aimed at researching the components of the phonetic level of speech, namely phonetic perception (the ability to differentiate phonemes that are similar in sound, distinguish a sound from a group of sounds, determine the sound in a word), phonetic analysis (the ability to determine the first and last sounds in a word, as well as the number of sounds in a word) and phonetic representation (the ability to correlate sounds with the name of an object) in older preschool children with normotypical psychophysical development and speech disorders. The results of the ascertainment experiment indicate that there are significant differences in the formation of the phonemic level of speech between the groups of the studied older preschool children with logopathology and those with normotypical psychophysical development. Phonemic processes in preschoolers with logopathology, as compared with normotypical indicators, develop with a delay, which leads to a number of errors: during phonemic perception, children do not recognize close-sounding sounds; do not know how to distinguish a sound from a group of sounds or in a word; during phonetic analysis – they incorrectly detect the first and last sounds in a word (name the first syllable or part of a word), make a mistake in determining the number of sounds in a word; during phonemic representation - cannot find the sound in the name of the object.

Effects of invisible lip movements on phonetic perception

We investigated whether ‘invisible’ visual information, i.e., visual information that is not consciously perceived, could affect auditory speech perception. Repeated exposure to McGurk stimuli (auditory /ba/ with visual [ga]) temporarily changes the perception of the auditory /ba/ into a ‘da’ or ‘ga’. This altered auditory percept persists even after the presentation of the McGurk stimuli when the auditory stimulus is presented alone (McGurk aftereffect). We used this and presented the auditory /ba/ either with or without (No Face) a masked face articulating a visual [ba] (Congruent Invisible) or a visual [ga] (Incongruent Invisible). Thus, we measured the extent to which the invisible faces could undo or prolong the McGurk aftereffects. In a further control condition, the incongruent faces remained unmasked and thus visible, resulting in four conditions in total. Visibility was defined by the participants’ subjective dichotomous reports (‘visible’ or ‘invisible’). The results showed that the Congruent Invisible condition reduced the McGurk aftereffects compared with the other conditions, while the Incongruent Invisible condition showed no difference with the No Face condition. These results suggest that ‘invisible’ visual information that is not consciously perceived can affect phonetic perception, but only when visual information is congruent with auditory information.

The effect of second language experience on lexical encoding of segments and tones

While previous studies generally find that increasing second language (L2) experience contributes to more accurate phonetic perception of L2 sounds, whether it leads to more proficient lexical encoding remains an empirical question. The current study examines lexical encoding of Mandarin segments and tones by English speakers at different proficiency levels. Eleven English speakers naïve to Mandarin, fifteen intermediate and nine advanced L2 learners participated in a word-learning experiment. After learning 16 Mandarin disyllabic words, they judged the matching between sound and meaning pairs, with half of the pairs being complete matches while the other containing segmental or tonal mismatches. The results showed that all groups were more sensitive to segmental than to tonal mismatches. The two learner groups outperformed the Naïve group in detecting segmental mismatches, but the three groups were equally inaccurate in rejecting tonal mismatches. The reaction times revealed, however, that the learners but not the Naïve group attended to tonal variations. These findings suggest that L2 experience has a clearer benefit for L2 segmental encoding than for tonal encoding, probably due to learners’ non-tonal language background. Experience in a tonal L2 enhances learners’ attention to the tones, but does not necessarily improve their accuracy in tonal encoding.

Arab EFL Learner Perceptions of English Phonemes: A Cross-Language Phonetic Interference

The extant studies addressing second language phonetic perception assume that second language phonemes are perceived to be similar to first language phonemes, and tend to be substituted by learners of English as a foreign language. This study aimed to assess the perceptual relationship between the phonemes of English and the sound units of Omani Arabic of the Al-Dakhiliyah region to discover the extent of the influence exerted by Omani Arabic on the perception of English phonemes by Omani learners. Two instruments were constructed to achieve this goal: first, the Omani phonetic system was elucidated via a questionnaire and the consonants and vowels uttered by the Omani people were archived as a phonetic dialect; second, a test was created to examine the perceptual phonetic distance between Omani Arabic and English phonemes. This investigation was designed to test the hypothesis of the revised speech learning model. The results confirmed the model’s postulation that learners instinctively and reflexively associate the second language sounds to the phonetic groups of their first language.

The non-native phonetic perception mechanism utilized by bilinguals with different L2 proficiency levels

Aims: The present study investigated whether bilinguals differing in L2 proficiency are different in their non-native phonetic perception mechanism. Methodology: An event-related potential (ERP) experiment was conducted, in which high and low L2 proficiency bilinguals were asked to focus their attention on a muted film while listening pre-attentively to phoneme contrasts arranged in the Oddball paradigm. Non-native and native phonetic conditions were investigated in two separate blocks. Data and analysis: The mean amplitudes of the ERP epochs time-locked to the onset of phonemes were analyzed within four consecutive time windows: 50–150 ms, 150–250 ms, 250–350 ms, and 350–600 ms. Repeated measures analyses were performed on the following factors: phonetic condition (non-native vs. native) × deviancy (standard vs. deviant) × brain region (frontal vs. parietal) × proficiency (high vs. low). Phonetic condition, deviancy, and brain region were within-subjects factors, whereas proficiency was a between-subjects factor. Findings: In the non-native phonetic condition, a deviancy effect in the form of mismatch negativity (MMN) and late discriminative negativity (LDN) ERP components was observed in bilinguals with high L2 proficiency, whereas the P3b and late positive component (LPC) were found in those with low L2 proficiency. In the native phonetic condition, the two proficiency groups were the same in the deviancy effect as manifested by their similar brain responses in the form of the MMN component. Originality: This was the first study to take native phonetic condition into consideration while investigating the relationship between L2 proficiency and non-native phonetic discrimination. Significance/implications: The current findings suggest that high L2 proficiency might be related to faster involuntary phonetic discrimination and efficient high-level phonetic evaluation, whereas low L2 proficiency bilinguals may need to rely on additional memory processing. Findings of this study provide more evidence for the perceptual plasticity in pre-attentive non-native phonetic processing as a function of L2 proficiency.

Power mediates the processing of gender during sibilant categorization

Prior studies suggest that listeners are more likely to categorize a sibilant ranging acoustically from [∫] to [s] as /s/ if provided auditory or visual information about the speaker that suggests male gender. Social cognition can also be affected by experimentally induced differences in power. A powerful individual’s impression of another tends to show greater consistency with the other person’s broad social category, while a powerless individual’s impression is more consistent with the specific pieces of information provided about the other person. This study investigated whether sibilant categorization would be influenced by power when the listener is presented with inconsistent sources of information about speaker gender. Participants were experimentally primed for behavior consistent with powerful or powerless individuals. They then completed a forced choice identification task: They saw a visual stimulus (a male or female face) and categorized an auditory stimulus (ranging from ‘shy’ to ‘sigh’) as /∫/ or /s/. As expected, participants primed for high power were sensitive to a single cue to gender, while those who received the low power prime were sensitive to both, even if the cues did not match. This result suggests that variability in listener power may cause systematic differences in phonetic perception.

Errors on a Speech-in-Babble Sentence Recognition Test Reveal Individual Differences in Acoustic Phonetic Perception and Babble Misallocations.

The ability to recognize words in connected speech under noisy listening conditions is critical to everyday communication. Many processing levels contribute to the individual listener's ability to recognize words correctly against background speech, and there is clinical need for measures of individual differences at different levels. Typical listening tests of speech recognition in noise require a list of items to obtain a single threshold score. Diverse abilities measures could be obtained through mining various open-set recognition errors during multi-item tests. This study sought to demonstrate that an error mining approach using open-set responses from a clinical sentence-in-babble-noise test can be used to characterize abilities beyond signal-to-noise ratio (SNR) threshold. A stimulus-response phoneme-to-phoneme sequence alignment software system was used to achieve automatic, accurate quantitative error scores. The method was applied to a database of responses from normal-hearing (NH) adults. Relationships between two types of response errors and words correct scores were evaluated through use of mixed models regression. Two hundred thirty-three NH adults completed three lists of the Quick Speech in Noise test. Their individual open-set speech recognition responses were automatically phonemically transcribed and submitted to a phoneme-to-phoneme stimulus-response sequence alignment system. The computed alignments were mined for a measure of acoustic phonetic perception, a measure of response text that could not be attributed to the stimulus, and a count of words correct. The mined data were statistically analyzed to determine whether the response errors were significant factors beyond stimulus SNR in accounting for the number of words correct per response from each participant. This study addressed two hypotheses: (1) Individuals whose perceptual errors are less severe recognize more words correctly under difficult listening conditions due to babble masking and (2) Listeners who are better able to exclude incorrect speech information such as from background babble and filling in recognize more stimulus words correctly. Statistical analyses showed that acoustic phonetic accuracy and exclusion of babble background were significant factors, beyond the stimulus sentence SNR, in accounting for the number of words a participant recognized. There was also evidence that poorer acoustic phonetic accuracy could occur along with higher words correct scores. This paradoxical result came from a subset of listeners who had also performed subjective accuracy judgments. Their results suggested that they recognized more words while also misallocating acoustic cues from the background into the stimulus, without realizing their errors. Because the Quick Speech in Noise test stimuli are locked to their own babble sample, misallocations of whole words from babble into the responses could be investigated in detail. The high rate of common misallocation errors for some sentences supported the view that the functional stimulus was the combination of the target sentence and its babble. Individual differences among NH listeners arise both in terms of words accurately identified and errors committed during open-set recognition of sentences in babble maskers. Error mining to characterize individual listeners can be done automatically at the levels of acoustic phonetic perception and the misallocation of background babble words into open-set responses. Error mining can increase test information and the efficiency and accuracy of characterizing individual listeners.

Early Detection of Parkinson’s and Alzheimer’s Diseases using the VOT_Mean Feature

Alzheimer’s (AD) and Parkinson’s diseases (PD) are tw of the most common neurological diseases in the world. Several studies have been conducted on the identification of these diseases using speech and laryngeal disorders. Those symptoms can appear even at the early stages of AD and PD, but not in very specific and prominent ways. Voice Onset Time (VOT) is an acoustic specification of the stopping consonant that is commonly discussed in studies of phonetic perception. In this study, the VOT_Mean feature was explored to identify AD and PD early using /pa/, /ka/, and /ta/ syllables for the diadochokinetic task (DDK). VOT_Mean was calculated as the average of the first and the second VOT values (VOT_1 and VOT_2), corresponding to the second and the penultimate VOT measurement cycles. Experimental tests were performed on Tunisian Arabic and Spanish databases for the early detection of AD and PD respectively. The results showed a very high significance of VOT_Mean on the early detection of AD and PD. Moreover, the best results were achieved using the XGBoost (XGBT) algorithm as a classifier on the VOT_Mean feature.

Lexical Influences on Categorical Speech Perception Are Driven by a Temporoparietal Circuit.

Categorical judgments of otherwise identical phonemes are biased toward hearing words (i.e., "Ganong effect") suggesting lexical context influences perception of even basic speech primitives. Lexical biasing could manifest via late stage postperceptual mechanisms related to decision or, alternatively, top-down linguistic inference that acts on early perceptual coding. Here, we exploited the temporal sensitivity of EEG to resolve the spatiotemporal dynamics of these context-related influences on speech categorization. Listeners rapidly classified sounds from a /gɪ/-/kɪ/ gradient presented in opposing word-nonword contexts (GIFT-kift vs. giss-KISS), designed to bias perception toward lexical items. Phonetic perception shifted toward the direction of words, establishing a robust Ganong effect behaviorally. ERPs revealed a neural analog of lexical biasing emerging within ∼200 msec. Source analyses uncovered a distributed neural network supporting the Ganong including middle temporal gyrus, inferior parietal lobe, and middle frontal cortex. Yet, among Ganong-sensitive regions, only left middle temporal gyrus and inferior parietal lobe predicted behavioral susceptibility to lexical influence. Our findings confirm lexical status rapidly constrains sublexical categorical representations for speech within several hundred milliseconds but likely does so outside the purview of canonical auditory-sensory brain areas.

The gender factor in the perception of English segments by non-native speakers

The aim of the paper is to present the findings of an empirical study which contributes to the ongoing research into gender effects on second language acquisition by exploring a biological influence on L2 pronunciation learning. One of the most frequent arguments used to vindicate single-sex education is that there are substantial sensory and perceptual differences between males and females which rationalize gender-specific teaching methods and gender-segregation at schools. The present study provides some preliminary insights into the perception of selected phonetic contrasts by Polish secondary school learners with the aim of investigating gender-based similarities and differences in the accuracy of sound recognition by males and females. The findings suggest that a commonly cited female advantage in acquiring L2 pronunciation cannot be attributed to their superior phonetic perception, as male participants performed equally well and identified the same number of English segments correctly.

Phonetic perception but not perception of speaker gender is impaired in chronic tinnitus.

While tinnitus is known to compromise the perception of speech, it is unclear if the same holds for extralinguistic speaker information. Furthermore, research with simple tone stimuli showed that unilateral tinnitus binds spatial attention, thereby impeding the detection of auditory changes in the non-affected ear. Using dichotic listening tasks, we tested left-ear tinnitus patients and control patients for their ability to ignore speech and speaker information in the task-irrelevant ear. To this end they heard vowel-consonant-vowel (VCV) syllables simultaneously spoken by gender-ambiguous voices in one ear and male or female voices in the contralateral ear. They selectively attended to speech (Exp. 1) or speaker (Exp. 2) information in a designated target ear, by classifying either the consonant (/b/ or /g/) in VCV syllables or voice gender (male or female) while ignoring distractor voices in the other ear. While performance was comparable across groups in the gender task, tinnitus patients responded slower than controls in the consonant task, with no effect of target ear. This suggests that tinnitus hampers phonetic perception in speech, while preserving the processing of extralinguistic speaker information. These findings support the growing evidence for speech perception impairments in tinnitus.

Harnessing the musician advantage: Short-term musical training affects non-native cue weighting of linguistic pitch

Lexical tone languages like Mandarin Chinese require listeners to discriminate among different pitch patterns. A syllable spoken with a rising pitch (e.g. bí ‘nose’) carries a different meaning than the same syllable spoken with a falling pitch (e.g. bì ‘arm’). For native speakers (L1) of a non-tonal language, accurate perception of tones in a second language (L2) is notoriously difficult. Musicians, however, have typically shown an aptitude for lexical tone learning due to the unique perceptual demands of music. This study tested whether musical effects can be exploited to improve linguistic abilities in the general population. A pre-test, 8-week training, post-test design was used to measure L1 English participants’ sensitivity to tone. Individual Differences Scaling was used to measure participants’ weighting of pitch height and movement cues. Participants took part in classroom Mandarin learning only (+L2), musical ear training only (+Music), or classroom learning combined with musical training (+L2+Music). An L1 Mandarin group served as a baseline. At pre-test, mean sensitivity to tone and multidimensional scaling results were similar across all three L1 English groups. After training, all three L1 English groups improved in mean sensitivity, though only the +L2+Music group did so at a significant rate. Multidimensional scaling revealed that all groups increased their weighting of the more informative pitch movement cue at roughly equal rates. Short-term musical training thus affected change in cue weighting of linguistic pitch in a manner comparable to that occurring after a semester of L2 classroom learning. When combined with classroom learning, short-term musical training resulted in even greater sensitivity to pitch movement cues. These results contribute to models of music-language interaction and suggest that focused application of non-linguistic acoustic training can improve phonetic perception in ways that are relevant to language learning.

Categorical Auditory Working Memory in Crows.

SummaryThe ability to group sensory data into behaviorally meaningful classes and to maintain these perceptual categories active in working memory is key to intelligent behavior. Here, we show that carrion crows, highly vocal and cognitively advanced corvid songbirds, possess categorical auditory working memory. The crows were trained in a delayed match-to-category task that required them to flexibly match remembered sounds based on the upward or downward shift of the sounds' frequency modulation. After training, the crows instantaneously classified novel sounds into the correct auditory categories. The crows showed sharp category boundaries as a function of the relative frequency interval of the modulation. In addition, the crows generalized frequency-modulated sounds within a category and correctly classified novel sounds kept in working memory irrespective of other acoustic features of the sound. This suggests that crows can form and actively memorize auditory perceptual categories in the service of cognitive control of their goal-directed behaviors.

Cross-modal transfer of talker-identity learning.

A speech signal carries information about meaning and about the talker conveying that meaning. It is now known that these two dimensions are related. There is evidence that gaining experience with a particular talker in one modality not only facilitates better phonetic perception in that modality, but also transfers across modalities to allow better phonetic perception in the other. This finding suggests that experience with a talker provides familiarity with some amodal properties of their articulation such that the experience can be shared across modalities. The present study investigates if experience with talker-specific articulatory information can also support cross-modal talker learning. In Experiment 1 we show that participants can learn to identify ten novel talkers from point-light and sinewave speech, expanding on prior work. Point-light and sinewave speech also supported similar talker identification accuracies, and similar patterns of talker confusions were found across stimulus types. Experiment 2 showed these stimuli could also support cross-modal talker matching, further expanding on prior work. Finally, in Experiment 3 we show that learning to identify talkers in one modality (visual-only point-light speech) facilitates learning of those same talkers in another modality (auditory-only sinewave speech). These results suggest that some of the information for talker identity takes a modality-independent form.

Unveiling Phonetic Cue Weighting through a Web-Based Experimental Design of Phonetic Perception: Focusing on the High Front Vowels in English

Unveiling Phonetic Cue Weighting through a Web-Based Experimental Design of Phonetic Perception: Focusing on the High Front Vowels in English

Brainstem and early cortical auditory activities associated with language differences in acoustic cue weighting for voicing perception

The purpose of the present study was to identify neural activities reflecting language differences in acoustic cue weighting for phonetic perception. We examined whether brainstem and early cortical auditory responses to voice-onset time (VOT) and onset frequency of fundamental frequency (onset F0) were different between two groups of listeners, native Japanese speakers and Korean second-language learners of Japanese, who use a VOT and onset F0, respectively, as the primary perceptual cue for voicing. In the experiment, we measured auditory brainstem responses (ABRs) and cortical N1 response of the Japanese and Korean participants while listening to stop-consonant stimuli varying in VOT and onset F0 (10 ms and 80 Hz, 30 ms and 80 Hz, or 30 ms and 120 Hz). We found that the N1 response was much more sensitive to VOT distinction in the Japanese than Korean participants, although the distinction of onset F0 was not reflected in early cortical responses in either language groups. There was no obvious difference in the ABRs between the Japanese and Korean participants. These results suggest that early cortical auditory activity is related to the processing of acoustic cue weighting for phonetic perception, while brainstem auditory activity is stimulus-dependent.

Effects of Age and Cochlear Implantation on Spectrally Cued Speech Categorization.

Purpose Weighting of acoustic cues for perceiving place-of-articulation speech contrasts was measured to determine the separate and interactive effects of age and use of cochlear implants (CIs). It has been found that adults with normal hearing (NH) show reliance on fine-grained spectral information (e.g., formants), whereas adults with CIs show reliance on broad spectral shape (e.g., spectral tilt). In question was whether children with NH and CIs would demonstrate the same patterns as adults, or show differences based on ongoing maturation of hearing and phonetic skills. Method Children and adults with NH and with CIs categorized a /b/-/d/ speech contrast based on two orthogonal spectral cues. Among CI users, phonetic cue weights were compared to vowel identification scores and Spectral-Temporally Modulated Ripple Test thresholds. Results NH children and adults both relied relatively more on the fine-grained formant cue and less on the broad spectral tilt cue compared to participants with CIs. However, early-implanted children with CIs better utilized the formant cue compared to adult CI users. Formant cue weights correlated with CI participants' vowel recognition and in children, also related to Spectral-Temporally Modulated Ripple Test thresholds. Adults and child CI users with very poor phonetic perception showed additive use of the two cues, whereas those with better and/or more mature cue usage showed a prioritized trading relationship, akin to NH listeners. Conclusions Age group and hearing modality can influence phonetic cue-weighting patterns. Results suggest that simple nonlexical categorization tests correlate with more general speech recognition skills of children and adults with CIs.