Theories Of Speech Perception Research Articles

Frequency maDDers, but phonology and formality maTTer, too.

In cases of allophonic variation, the frequency of a variant has been claimed to influence phonological representations, affecting the perception and recognition of words. For example, Connine (2004) found stronger Ganong effects in words with frequent variants (e.g., intervocalic tap in the word pretty) than in words with infrequent variants (e.g., [t] in the word pretty). Specifically, in a phoneme‐monitoring task, listeners reported more PRETTY responses when listening to a pre[D]y‐bre[D]y continuum than a pre[t]y‐bre[t]y continuum. If this bias is due to variant frequency, we might expect this effect to generalize across variants, independent of other factors (context, within‐paradigm alternations). However, a diverse set of variants and alternate explanatory factors contributing to the effect have not yet been investigated. For example, the roles of paradigm variants (e.g., baiting‐bait versus pretty‐*pret) and filler type (e.g., testing for intervocalic [t] in the context of carefully versus casually articulated fillers) might also explain these effects. This study builds on Connine (2004) and examines both paradigmatic relations and filler type across two allophonic alternations (tapping, final [t] glottalization). Ultimately, the results show that variant frequency alone is insufficient to account for this effect. An integrated theory of speech perception is proposed.

Évaluation à 6 ans du langage de l’enfant né grand prématuré sans paralysie cérébrale : étude prospective de 55 enfants

Very premature birth carries a high risk of neurocognitive disabilities and learning disorders. Acquiring sufficient speech skills is crucial to good school performance.A prospective study was conducted in 2006 to evaluate speech development in 55 children born very prematurely in 2000 at the Rouen Teaching Hospital (Rouen, France), free of cerebral palsy, compared to 6-year-old born at full term. A computerized speech assessment tool was used (Bilan Informatisé du Langage Oral, BILO II).In the premature-birth group, 49 % of 6-year-old had at least 1 score below the 25th percentile on 1 of the 8 BILO II tests. Significant speech impairments were noted for 2 components of speech, namely, comprehension and phonology. Oral comprehension scores no higher than the 10th percentile were obtained by 23 % of prematurely born children (P<0.02 vs controls). On word repetition tasks used to test phonology, 21 % of prematurely born children obtained scores no higher than the 10th percentile (P<0.01 vs controls). An evaluation of sensorimotor language prerequisites (constraints) in 30 of the 55 prematurely born children showed significant differences with the controls for word memory, visual attention, and buccofacial praxis.The speech development impairments found in 6-year-old born very prematurely suggest a distinctive pattern of neurodevelopmental dysfunction that is consistent with the motor theory of speech perception.

Teaching and Learning Guide for: Mirror Neurons, the Motor System, and Language – From the Motor Theory to Embodied Cognition and Beyond

Teaching and Learning Guide for: Mirror Neurons, the Motor System, and Language – From the Motor Theory to Embodied Cognition and Beyond

Vowel constrictions are recoverable from formants

The area function of the vocal tract in all of its spatial detail is not directly computable from the speech signal. But is partial, yet phonetically distinctive, information about articulation recoverable from the acoustic signal that arrives at the listener's ear? The answer to this question is important for phonetics, because various theories of speech perception predict different answers. Some theories assume that recovery of articulatory information must be possible, while others assume that it is impossible. However, neither type of theory provides firm evidence showing that distinctive articulatory information is or is not extractable from the acoustic signal. The present study focuses on vowel gestures and examines whether linguistically significant information, such as the constriction location, constriction degree, and rounding, is contained in the speech signal, and whether such information is recoverable from formant parameters. Perturbation theory and linear prediction were combined, in a manner similar to that in Mokhtari (1998) [Mokhtari, P. (1998). An acoustic-phonetic and articulatory study of speech-speaker dichotomy. Doctoral dissertation, University of New South Wales], to assess the accuracy of recovery of information about vowel constrictions. Distinctive constriction information estimated from the speech signal for ten American English vowels were compared to the constriction information derived from simultaneously collected X-ray microbeam articulatory data for 39 speakers [ Westbury (1994). Xray microbeam speech production database user's handbook. University of Wisconsin, Madison, WI]. The recovery of distinctive articulatory information relies on a novel technique that uses formant frequencies and amplitudes, and does not depend on a principal components analysis of the articulatory data, as do most other inversion techniques. These results provide evidence that distinctive articulatory information for vowels can be recovered from the acoustic signal.

The role of mirror neurons in speech perception and action word semantics

The discovery of mirror neurons in the macaque monkey has ignited intense interest in motor theories of cognition, including speech and language. Here we examine two such claims, that the perception of speech sounds critically depends on motor representations of speech gestures (the motor theory of speech perception) and that the representation of action-related semantic knowledge critically depends on motor representations involved in performing actions. We conclude that there is strong evidence against the claim that speech perception critically depends on the motor system and that there is no conclusive evidence in support of the view that the motor system supports action semantics. We propose instead that motor-related activity during perceptual processes stem from spreading activation in sensory-motor networks that are critical for speech and language production.

The interaction between acoustic salience and language experience in developmental speech perception: evidence from nasal place discrimination

Previous research suggests that infant speech perception reorganizes in the first year: young infants discriminate both native and non-native phonetic contrasts, but by 10-12 months difficult non-native contrasts are less discriminable whereas performance improves on native contrasts. In the current study, four experiments tested the hypothesis that, in addition to the influence of native language experience, acoustic salience also affects the perceptual reorganization that takes place in infancy. Using a visual habituation paradigm, two nasal place distinctions that differ in relative acoustic salience, acoustically robust labial-alveolar [ma]-[na] and acoustically less salient alveolar-velar [na]-[ enga], were presented to infants in a cross-language design. English-learning infants at 6-8 and 10-12 months showed discrimination of the native and acoustically robust [ma]-[na] (Experiment 1), but not the non-native (in initial position) and acoustically less salient [na]-[ enga] (Experiment 2). Very young (4-5-month-old) English-learning infants tested on the same native and non-native contrasts also showed discrimination of only the [ma]-[na] distinction (Experiment 3). Filipino-learning infants, whose ambient language includes the syllable-initial alveolar (/n/)-velar (/ eng/) contrast, showed discrimination of native [na]-[ enga] at 10-12 months, but not at 6-8 months (Experiment 4). These results support the hypothesis that acoustic salience affects speech perception in infancy, with native language experience facilitating discrimination of an acoustically similar phonetic distinction [na]-[ enga]. We discuss the implications of this developmental profile for a comprehensive theory of speech perception in infancy.

Word segmentation of American English /s/ in semi‐spontaneous speech.

To comprehend spoken language, listeners need to find words from a continuous stream of speech sounds. Little work has explored whether there are reliable acoustic cues to word boundaries in conversational speech, which is highly reduced and under‐articulated, potentially creating ambiguities at word boundaries. Segmentation may be even more difficult when the same segment repeats at a word boundary, ending the preceding word and beginning the following word (e.g., gas station). Segmentation in this environment was investigated by examining the production and perception of fricative /s/ in semi‐spontaneous speech. Twenty talkers produced sentences containing ambiguous two‐word sequences with /s/ between the two words. All sequences are interpretable in three ways (e.g., grow snails, gross snails, and gross nails) depending on how the frication is segmented. Acoustic analyses of the production data examined whether there are acoustic cues distinguishing the three versions of the ambiguous sequences. Listening experiments using the talkers’ productions as stimuli evaluated the degree of ambiguity in the tokens and identified acoustic cues that listeners use to segment the two words. Results will be discussed in the context of theories of speech perception and word segmentation.

Premotor cortex mediates perceptual performance

Articulatory goals have long been proposed to mediate perception. Examples include direct realist and constructivist (analysis by synthesis) theories of speech perception. Although the activity in brain regions involved with action production has been shown to be present during action observation (Mirror Neuron System), the relationship of this activity to perceptual performance has not been clearly demonstrated at the event level. To this end we used functional magnetic resonance imaging fMRI and magnetoencephalography MEG to measure brain activity for correct and incorrect trials of an auditory phonetic identification in noise task. FMRI analysis revealed activity in the premotor cortex including the neighboring frontal opercular part of Broca's area (PMC/Broca's) for both perception and production tasks involving the same phonetic stimuli (potential mirror system site) that was significantly greater for correct over incorrect perceptual identification trials. Time–frequency analysis of single trials conducted over MEG current localized to PMC/Broca's using a hierarchical variational Bayesian source analysis technique revealed significantly greater event-related synchronization ERS and desynchronization ERD for correct over incorrect trials in the alpha, beta, and gamma frequency range prior to and after stimulus presentation. Together, these fMRI and MEG results are consistent with the hypothesis that articulatory processes serve to facilitate perceptual performance, while further dispelling concerns that activity found in ventral PMC/Broca's (mirror system) is merely a product of covert production of the perceived action. The finding of performance predictive activity prior to stimulus onset as well as activity related to task difficulty instead of information available in stimulation are consistent with constructivist and contrary to direct realist theories of perception.

The Perception-for-Action-Control Theory (PACT): A perceptuo-motor theory of speech perception

It is an old-standing debate in the field of speech communication to determine whether speech perception involves auditory or multisensory representations and processing, independently on any procedural knowledge about the production of speech units or on the contrary if it is based on a recoding of the sensory input in terms of articulatory gestures, as posited in the Motor Theory of Speech Perception. The discovery of mirror neurons in the last 15 years has strongly renewed the interest for motor theories. However, while these neurophysiological data clearly reinforce the plausibility of the role of motor properties in perception, it could lead in our view to incorrectly de-emphasise the role of perceptual shaping, crucial in speech communication. The so-called Perception-for-Action-Control Theory (PACT) aims at defining a theoretical framework connecting in a principled way perceptual shaping and motor procedural knowledge in speech multisensory processing in the human brain. In this paper, the theory is presented in details. It is described how this theory fits with behavioural and linguistic data, concerning firstly vowel systems in human languages, and secondly the perceptual organization of the speech scene. Finally a neuro-computational framework is presented in connection with recent data on the possible functional role of the motor system in speech perception.

Distinctive features: Phonological underspecification in representation and processing

Phonological variation of any sort (determined by speech styles, phrasing, or morphophonological rules) affecting the shapes of words and morphemes are a matter of concern for theories of speech perception and language comprehension. To come to grips with parsing the speech stream, accessing the lexicon and ultimately recognizing words, both representational as well as processing issues must be considered. The central questions in the research presented here are: W hat is represented in the mental lexicon? H ow is it represented? H ow is the speech signal parsed and information mapped onto the mental lexicon? In this paper we will address four issues within the framework of our Featurally Underspecified Lexicon model (FUL): (a) our assumptions concerning distinctive feature organization defined by phonological, perceptual and acoustic constraints; (b) specification of features in the mental lexicon (based on universal and language specific requirements); (c) extracting distinctive features from the signal; (d) mapping features from the signal to the lexicon. We claim that phonological features are extracted from the variable acoustic signal based on broad acoustic properties. A three-way matching algorithm maps these features onto highly abstract phonological mental representations. We provide evidence from synchronic phonological analyses, language change, psycholinguistic and neurolinguistic data.

A Study on Perceptual Compensation for /u/-fronting in American English

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Mirror Neurons, the Motor System and Language: From the Motor Theory to Embodied Cognition and Beyond

AbstractThe motor theory of speech perception states that phonetic segments in the acoustic speech stream activate stored motor commands in the brain that give rise to perception of discrete speech sounds. The motor theory fell out of favor when growing evidence from lesion and behavioral studies led aspects of the theory to appear untenable. However, with the recent discovery of mirror neurons and their potential role in action understanding, interest in the motor theory of speech perception is renewed. We review the function and properties of mirror neurons in monkeys, and briefly describe the current literature that focuses on the role of a putative human mirror system in cognition and language processing. Further, we describe proposed evidence for the involvement of the motor system in perceptive speech processing, and point out ambiguities in the literature that arise from the tight coupling of sensory and motor processes in speech comprehension. An alternative theory proposing that sensory representations in superior temporal cortex are mapped onto frontal production networks is offered. We cite evidence that confirms the failure of the motor theory to accurately describe perceptive processes in speech, and promote the conclusion that speech representations are fundamentally sensory in nature.

Language as gesture

Language can be understood as an embodied system, expressible as gestures. Perception of these gestures depends on the “mirror system,” first discovered in monkeys, in which the same neural elements respond both when the animal makes a movement and when it perceives the same movement made by others. This system allows gestures to be understood in terms of how they are produced, as in the so-called motor theory of speech perception. I argue that human speech evolved from manual gestures, with vocal gestures being gradually incorporated into the mirror system in the course of hominin evolution. Speech may have become the dominant mode only with the emergence of Homo sapiens some 170,100years ago, although language as a relatively complex syntactic system probably emerged over the past 2 million years, initially as a predominantly manual system. Despite the present-day dominance of speech, manual gestures accompany speech, and visuomanual forms of language persist in signed languages of the deaf, in handwriting, and even in such forms as texting.

Perceptuomotor compatibility effects in speech

Kerzel and Bekkering (2000) found perceptuomotor compatibility effects between spoken syllables and visible speech gestures and interpreted them as evidence in favor of the distinctive claim of the motor theory of speech perception that the motor system is recruited for perceiving speech. We present three experiments aimed at testing this interpretation. In Experiment 1, we replicated the original findings by Kerzel and Bekkering but with audible syllables. In Experiments 2 and 3, we tested the results of Experiment 1 under more stringent conditions, with different materials and different experimental designs. In all of our experiments, we found the same result: Perceiving syllables affects uttering syllables. The result is consistent both with the results of a number of other behavioral and neural studies related to speech and with more general findings of perceptuomotor interactions. Taken together, these studies provide evidence in support of the motor theory claim that the motor system is recruited for perceiving speech.

Visual speech primes open-set recognition of spoken words

Visual speech perception has become a topic of considerable interest to speech researchers. Previous research has demonstrated that perceivers neurally encode and use speech information from the visual modality, and this information has been found to facilitate spoken word recognition in tasks such as lexical decision (Kim, Davis, & Krins, 2004). In this paper, we used a cross-modality repetition priming paradigm with visual speech lexical primes and auditory lexical targets to explore the nature of this priming effect. First, we report that participants identified spoken words mixed with noise more accurately when the words were preceded by a visual speech prime of the same word compared with a control condition. Second, analyses of the responses indicated that both correct and incorrect responses were constrained by the visual speech information in the prime. These complementary results suggest that the visual speech primes have an effect on lexical access by increasing the likelihood that words with certain phonetic properties are selected. Third, we found that the cross-modality repetition priming effect was maintained even when visual and auditory signals came from different speakers, and thus different instances of the same lexical item. We discuss implications of these results for current theories of speech perception.

The nature and time course of the relationship between surface variability and linguistic processing.

It is becoming increasingly prevalent to study and understand the role of surface information in the process of speech perception and to attempt to accommodate these variables in theories of speech perception. Indeed, theories of speech perception increasingly require an account of the precise circumstances under which surface details affect the ease with which listeners access spoken words. To date, the majority of studies have focused on manipulating various components of surface information (e.g., speaking rate, talker differences, dialect difference, and so on) to determine whether these manipulations matter to the processing task. The present set of studies in our laboratory represents the converse component of this relationship in order to determine whether linguistic complexity can affect or modulate listeners’ overt subjective impressions of the surface information. Two different methodologies, including semantic priming and repetition priming, were used manipulate ease of lexical access and determine the role on listeners perception of surface details (foreign accent). Additionally, the time course of the effect of linguistic context on accent rating judgments was studied as it manifested itself differently at different points during perceptual processing. Overall, these studies help understand the complex nature of the relationship between surface variability and linguistic processing.

The impact of native inventory versus native contrast on vowel discrimination.

Theories of speech perception differ as to whether experience with sounds or with sound contrasts is more important when discriminating novel sounds. To explore this question, 21 American English, 16 Turkish, and 16 French speakers were tested on their ability to discriminate high front vowels in German (/i/∼/y/∼/Y/∼/I/). The crucial difference between the participant languages is that English only uses the tense‐lax contrast (/i/∼/I/), while Turkish and French only use the rounding contrast (/i/∼/y/). If contrast is crucial, then English speakers should be better at discriminating /y/∼/Y/, whereas if the inventory is crucial, then they should be better at discriminating /I/∼/Y/. The results of a fixed discrimination task show that there is no significant effect of language and that the tense‐lax contrast (/i/∼/I/; /y/∼/Y/) is universally more easily discriminated than the rounding contrast (/i/∼/y/; /I/∼/Y/). The results of a rating task do reflect an influence of language, however with English‐listeners...

A little more conversation, a little less action — candidate roles for the motor cortex in speech perception

The motor theory of speech perception assumes that activation of the motor system is essential in the perception of speech. However, deficits in speech perception and comprehension do not arise from damage that is restricted to the motor cortex, few functional imaging studies reveal activity in the motor cortex during speech perception, and the motor cortex is strongly activated by many different sound categories. Here, we evaluate alternative roles for the motor cortex in spoken communication and suggest a specific role in sensorimotor processing in conversation. We argue that motor cortex activation is essential in joint speech, particularly for the timing of turn taking.

Speech Perception: Motoric Contributions versus the Motor Theory

Recent studies indicate that the motor cortex is involved not only in the production of speech, but also in its perception. These studies have sparked a renewed interest in gesture-based theories of speech perception.

The Motor Somatotopy of Speech Perception

Listening to speech recruits a network of fronto-temporo-parietal cortical areas. Classical models consider anterior (motor) sites to be involved in speech production whereas posterior sites are considered to be involved in comprehension. This functional segregation is challenged by action-perception theories suggesting that brain circuits for speech articulation and speech perception are functionally dependent. Although recent data show that speech listening elicits motor activities analogous to production, it's still debated whether motor circuits play a causal contribution to the perception of speech. Here we administered transcranial magnetic stimulation (TMS) to motor cortex controlling lips and tongue during the discrimination of lip- and tongue-articulated phonemes. We found a neurofunctional double dissociation in speech sound discrimination, supporting the idea that motor structures provide a specific functional contribution to the perception of speech sounds. Moreover, our findings show a fine-grained motor somatotopy for speech comprehension. We discuss our results in light of a modified "motor theory of speech perception" according to which speech comprehension is grounded in motor circuits not exclusively involved in speech production.