Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PHONETICS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed1982

Impairment of phonetic reading in dyslexia and its persistence beyond childhood--research note.

A previous analysis of the historical development of writing towards progressive phonetisation gave rise to the hypothesis that disorders of reading arise from a defective processing of spoken sounds. Sixteen adolescent and adult dyslexic patients were studied, 10 of whom had been followed up from childhood. A newly devised test of phonetic reading proved superior to the Schonell reading test in distinguishing dyslexics from normals, and mirrored the original severity of the disorder. A phonetic writing test was less useful. The findings support the view that dyslexia is due to a defect of verbal processing which may persist beyond childhood.

Adolescent↗
PubMed2006

Phonological versus phonetic cues in native and non-native listening: Korean and Dutch listeners' perception of Dutch and English consonants.

We investigated how listeners of two unrelated languages, Korean and Dutch, process phonologically viable and nonviable consonants spoken in Dutch and American English. To Korean listeners, released final stops are nonviable because word-final stops in Korean are never released in words spoken in isolation, but to Dutch listeners, unreleased word-final stops are nonviable because word-final stops in Dutch are generally released in words spoken in isolation. Two phoneme monitoring experiments showed a phonological effect on both Dutch and English stimuli: Korean listeners detected the unreleased stops more rapidly whereas Dutch listeners detected the released stops more rapidly and/or more accurately. The Koreans, however, detected released stops more accurately than unreleased stops, but only in the non-native language they were familiar with (English). The results suggest that, in non-native speech perception, phonological legitimacy in the native language can be more important than the richness of phonetic information, though familiarity with phonetic detail in the non-native language can also improve listening performance.

Analysis of Variance↗
PubMed1979

Auditory versus phonetic accounts of observed confusions between consonant phonemes.

The utility of phonetic features versus acoustic properties for describing perceptual relations among speech sounds was evaluated with a multidimensional scaling analysis of Miller and Nicely's [J. Acoust. Soc. Am. 27, 338-352 (1955)] consonant confusions data. The INDSCAL method and program were employed with the original data log transformed to enhance consistency with the linear INDSCAL model. A four-dimensional solution accounted for 69% of the variance and was best characterized in terms of acoustic properties of the speech signal, viz., temporal relationship of periodicity and burst onset, shape of voiced first formanant transition, shape of voiced second formanant transition, and amount of initial spectral dispersion, rather than in terms of phonetic features. The amplitude and spectral location of acoustic energy specifying each perceptual dimension were found to determine a dimension's perceptual effect as the signal was degraded by masking noise and bandpass filtering. Consequently, the perceptual bases of identification confusions between pairs of syllables were characterized in terms of the shared acoustic properties which remained salient in the degraded speech. Implications of these findings for feature-based accounts of perceptual relationships between phonemes are considered.

Female↗
PubMed1981

Phonetic perception: evidence for context-dependent and context-independent processing.

In a series of experiments a selective adaptation technique was used to examine the dependencies that arise in processing phonetically relevant acoustic information in syllable-initial consonants. The pattern of results, identical across two vowel contexts, indicated that voice-onset-time specifying a voicing contrast and the spectral form of the initial transitions specifying a place of articulation contrast are processed in a mutually dependent fashion. A different pattern was revealed, however, for the processing of the spectral form of the transitions specifying a place contrast and the duration of the transitions specifying a manner contrast. Specifically, the data indicated that transition duration is processed independently of the spectral characteristics of the transitions, even though the processing of the spectral characteristics of the transitions is dependent on their duration. On the basis of these findings, the following conclusions were drawn: First, there are distinct patterns of interaction during speech processing; second, the system does not operate entirely in a context-conditioned fashion; and third, at early stages of processing the speech signal is not treated holistically, but rather undergoes analysis in terms of those acoustic dimensions that provide information about phonetic distinctions.

Humans↗
PubMed1982

Differences between spectral dependencies in auditory and phonetic temporal processing: Relevance to the perception of voicing in initial stops.

Untrained listeners can reliably judge the temporal order of the onset of (a) pairs of coterminous tones [forming tone-onset-time (TOT) continua], and (b) higher-frequency bandlimited noises and lower-frequency bandlimited pulse trains [forming noise-onset-time (NOT) continua], but only if the onset of the second sound lags the first by at least 15-20 ms. It has been argued that the limitation of auditory temporal-order resolution that gives rise to this threshold also underlies the distinction between voiced [b, d, g] and voiceless aspirated [ph, th, kh] syllable-initial stop constants [which can be expressed in differences of voice-onset-time. (VOT)]. The positions of boundaries between phonetic categories on VOT continua depend on the values of a variety of spectral parameters, including the onset frequency of the first formant; lowering this results in boundaries shifting to longer values of VOT. The present experiment demonstrated that analogous spectral manipulations applied to the members of TOT and NOT continua do not result in systematic shifts in the location of the simultaneity-successivity threshold. The result suggest that the role of F1 in the perception of voicing does not have a purely auditory basis, a conclusion compatible with certain development and cross-language studies that have demonstrated that sensitivity to F1 is acquired and language dependent. The threshold may determine ranges of VOT between which auditory contrast is heightened, and so have helped to shape the preferred phonetic forms of phonological distinctions in the world's languages. However, other factors, such a production constraints or arbitrary processes of cultural development, appear to be required to account for the positions of voicing boundaries in particular languages.

Auditory Perception↗
PubMed1986

The use of auditory and phonetic memory in vowel discrimination.

A commonly held assumption about memory for speech is that auditory memory is referred to only if phonetic memory does not contain the information needed for a particular trial. However, this assumption is in conflict with recent evidence [Crowder, J. Exp. Psychol.: Learning, Memory, Cognition 8, 153-162 (1982); Repp et al., J. Exp. Psychol.: Human Perception Performance 5, 129-145 (1979)]. The present study provides additional data to help determine how auditory and phonetic memory are used in a vowel discrimination task, and what happens during memory decay. Experiment 1 was conducted to determine whether performance levels decline at similar rates on between- and within-category AX vowel comparison trials when certain methodological problems are removed. This was confirmed. Experiment 2 demonstrated that in the AX task there is a vowel order effect, as Repp et al. found, but that this effect increased across interstimulus delay intervals, in contrast to their findings. The results can be accommodated with a model in which the memory for a vowel is represented as a small, bounded area within the vowel space, and in which memory decay is represented by the expansion of that bounded area over time.

Adolescent↗
PubMed1991

Cross-language speech perception in adults: phonemic, phonetic, and acoustic contributions.

Cross-language studies have shown that foreign consonant contrasts vary in the degree of perceptual difficulty which they present adult non-native listeners. Phonemic, phonetic, and acoustic factors have been considered important in accounting for this variability. These factors were examined by comparing English listeners' perception of the Hindi retroflex versus dental place-of-articulation contrast in four different voicing contexts: voiceless unaspirated, breathy voiced, voiceless aspirated, and prevoiced. Differences in perceptual difficulty of the four contrasts were predicted based on (1) phonemic status (the functional status of the contrast in the listeners' native phonology), (2) phonetic experience (as allophones or free variants), and (3) differences in acoustic salience related to voicing. Performance was not "nativelike" for any of the four contrasts; however, significant differences in perceptual difficulty among the four contrasts were evident. Perceptual differences were correlated with both acoustic salience of place cues and subjects' descriptions of their assimilation strategies.

Acoustics↗
PubMed1992

Phonetic prototypes: influence of place of articulation and speaking rate on the internal structure of voicing categories.

In this investigation, the effects of context on the perception of voicing contrasts specified by voice-onset-time (VOT) in syllable-initial stop consonants were examined. In an earlier paper [J.L. Miller and L.E. Volaitis, Percept. Psychophys. 46, 505-512 (1989)], it was reported that the listener's adjustment for one contextual variable, speaking rate, was not confined to the region of the phonetic category boundary, but extended throughout the phonetic category. The current investigation examines whether this type of perceptual remapping also occurs for another contextual variable, the place of articulation of the syllable-initial consonant. In a preliminary experiment that involved acoustic measurement of natural speech, it was confirmed that as place of articulation moves from labial to velar, VOT increases, and it was established that this occurs across a range of speaking rates (syllable durations). In the main experiments, which focused on the voiceless category, it was found that this acoustic change was reflected in perception not only as a shift in the location of the voiced-voiceless category boundary, but also a change in both the specific range of stimuli identified as members of the voiceless category and the set of stimuli judged to be the best exemplars, or prototypes, of the category. These findings extend earlier research by showing that a change in place of articulation, like a change in speaking rate, systematically alters the internal perceptual structure of voicing categories.

Adult↗
PubMed1992

Structural design of hidden Markov model speech recognizer using multivalued phonetic features: comparison with segmental speech units.

A novel approach to speech recognition, on the basis of a multidimensional multivalued phonetic-feature description of speech signals, is presented and evaluated. The hidden Markov model (HMM) framework is used to provide the recognition algorithm, which assumes that the underlying Markov chain tracks the temporal evolution of the features. It is shown that this approach can naturally accommodate such coarticulatory effects as feature spreading and formant transition in the functionality of the recognizer, and can provide a high degree of acoustic data sharing that makes effective use of training data. Use of phonetic features as the basic speech units creates a framework where the Markov model's state topology in the recognizer can be designed with guidance of detailed speech knowledge. Details of such a design for a stop consonant-vowel vocabulary are described. Experimental results on the task of speaker-dependent stop consonant discrimination, evaluated from speech data from a total of ten male and five female speakers, demonstrate effectiveness of this feature-based recognizer. Over the 15 speakers, the error rates were shown to be reduced by 23%, 37%, 42%, and 38%, respectively, compared with the conventional HMM-based recognition methods using words, phonemes, allophones, and microsegments as the primary speech units.

Communication↗
PubMed1993

A cross-linguistic investigation of locus equations as a phonetic descriptor for place of articulation.

A previous study [H. Sussman, H. McCaffrey, and S. Matthews, J. Acoust. Soc. Am. 90, 1309-1325 (1991)] of American English CV coarticulation showed a remarkably linear relationship between onset frequencies of F2 transitions, plotted on the y axis, in relation to the F2 midvowel "target" frequencies, plotted on the x axis, for CVC tokens with initial [b d g] and ten medial vowel contexts. Slope and y-intercept values of regression functions fit to these scatterplots ("locus equations") were shown to serve as statistically powerful phonetic descriptors of place of articulation. The present study extends the locus equation metric to three additional languages--Thai, Cairene Arabic, and Urdu--having both two and four place contrasts for syllable-initial voiced stops. A total of 14 speakers (Thai = 6, Arabic = 3, Urdu = 5) produced 1740 CVC tokens that were acoustically analyzed using MacSpeech Lab II. Strong linear regression relationships were found for every stop category across all speakers. Slopes and y intercepts systemically varied as a function of place of articulation. Cross-language comparisons of stop place categories were performed but variability of slope and y intercept means tempered conclusions concerning the existence of CV "phonetic hot spots."

Adult↗
PubMed1994

The influence of sentential speaking rate on the internal structure of phonetic categories.

In the experiments reported in this paper we compared the effects of syllable-level and sentence-level speaking rate on phonetic perception. In an earlier set of experiments, we found that syllable-level rate influences the internal perceptual structure of phonetic categories [Miller and Volaitis, Percept. Psychophys. 46, 505-512 (1989); Volaitis and Miller, J. Acoust. Soc. Am. 92, 723-735 (1992)]. Specifically, a change in target-syllable rate altered the location of the stimuli judged to be the best category exemplars, as well as the width of this best-exemplar range. In the present investigation, it was asked whether sentence-level rate has the same influence. It was found that slowing sentence rate shifted the location of the best-exemplar range, but did not alter its width. These findings are discussed in terms of timing mechanisms that may operate during speech perception.

Acoustic Stimulation↗
PubMed1996

Influences of phonetic identification and category goodness on American listeners' perception of /r/ and /l/.

Recent experiments have demonstrated that category goodness influences the perception of vowels [Iverson and Kuhl, J. Acoust. Soc. Am. 97, 553-562 (1995)]; listeners show a perceptual magnet effect characterized by shrunken perceptual distances near excellent exemplars of vowel categories and stretched distances near poor exemplars. The present study extends this investigation by examining the relative influence of phonetic identification and category goodness on the perception of American English /r/ and /l/. Eighteen /ra/ and /la/ tokens were synthesized by varying F2 and F3 frequencies. Adult listeners identified and rated the goodness of individual stimuli, and rated the similarity of stimulus pairs. Multidimensional scaling analyses revealed that the perceptual space was shrunk near the best exemplars of each category and stretched near the category boundary. In addition, individual differences in /r/ identification corresponded to the degree of shrinking near the best exemplars of the /r/ category. The results demonstrate that category goodness and phonetic identification both contribute to the perception of /r/ and /l/.

Humans↗
PubMed1997

Speechreading and the structure of the lexicon: computationally modeling the effects of reduced phonetic distinctiveness on lexical uniqueness.

A lexical modeling methodology was employed to examine how the distribution of phonemic patterns in the lexicon constrains lexical equivalence under conditions of reduced phonetic distinctiveness experienced by speech-readers. The technique involved (1) selection of a phonemically transcribed machine-readable lexical database, (2) definition of transcription rules based on measures of phonetic similarity, (3) application of the transcription rules to a lexical database and formation of lexical equivalence classes, and (4) computation of three metrics to examine the transcribed lexicon. The metric percent words unique demonstrated that the distribution of words in the language substantially preserves lexical uniqueness across a wide range in the number of potentially available phonemic distinctions. Expected class size demonstrated that if at least 12 phonemic equivalence classes were available, any given word would be highly similar to only a few other words. Percent information extracted (PIE) [D. Carter, Comput. Speech Lang. 2, 1-11 (1987)] provided evidence that high-frequency words tend not to reside in the same lexical equivalence classes as other high-frequency words. The steepness of the functions obtained for each metric shows that small increments in the number of visually perceptible phonemic distinctions can result in substantial changes in lexical uniqueness.

Electronic Data Processing↗
PubMed2000

Neurophysiologic correlates of cross-language phonetic perception.

This study examined neurophysiologic correlates of the perception of native and nonnative phonetic categories. Behavioral and electrophysiologic responses were obtained from Hindi and English listeners in response to a stimulus continuum of naturally produced, bilabial CV stimuli that differed in VOT from -90 to 0 ms. These speech sounds constitute phonemically relevant categories in Hindi but not in English. As expected, the native Hindi listeners identified the stimuli as belonging to two distinct phonetic categories (/ba/ and /pa/) and were easily able to discriminate a stimulus pair across these categories. On the other hand, English listeners discriminated the same stimulus pair at a chance level. In the electrophysiologic experiment N1 and MMN cortical evoked potentials (considered neurophysiologic indices of stimulus processing) were measured. The changes in N1 latency which reflected the duration of pre-voicing across the stimulus continuum were not significantly different for Hindi and English listeners. On the other hand, in response to the /ba/-/pa/ stimulus contrast, a robust MMN was seen only in Hindi listeners and not in English listeners. These results suggest that neurophysiologic levels of stimulus processing reflected by the MMN and N1 are differentially altered by linguistic experience.

Cerebral Cortex↗
PubMed1992

Lateralization of phonetic and pitch discrimination in speech processing.

Cerebral activation was measured with positron emission tomography in ten human volunteers. The primary auditory cortex showed increased activity in response to noise bursts, whereas acoustically matched speech syllables activated secondary auditory cortices bilaterally. Instructions to make judgments about different attributes of the same speech signal resulted in activation of specific lateralized neural systems. Discrimination of phonetic structure led to increased activity in part of Broca's area of the left hemisphere, suggesting a role for articulatory recoding in phonetic perception. Processing changes in pitch produced activation of the right prefrontal cortex, consistent with the importance of right-hemisphere mechanisms in pitch perception.

Acoustic Stimulation↗
PubMed1997

Cross-language analysis of phonetic units in language addressed to infants.

In the early months of life, infants acquire information about the phonetic properties of their native language simply by listening to adults speak. The acoustic properties of phonetic units in language input to young infants in the United States, Russia, and Sweden were examined. In all three countries, mothers addressing their infants produced acoustically more extreme vowels than they did when addressing adults, resulting in a "stretching" of vowel space. The findings show that language input to infants provides exceptionally well-specified information about the linguistic units that form the building blocks for words.

Adult↗
PubMedDate not supplied

Investigating unscripted speech: implications for phonetics and phonology.

This paper looks at patterns of reduction and elaboration in speech production, taking the phenomenon of plosive-related glottalization in German spontaneous speech, on the basis of the 'Kiel Corpus', as its point of departure, and proposes general principles of human speech to explain them. This is followed by an enquiry into the nature of a production-perception link, based on complementary data from perceptual experiments. A hypothesis is put forward as to how listeners cope with the enormous phonetic variability of spoken language and how this ability may be acquired. Finally, the need for a new paradigm of phonetic analysis and phonological systematization is stressed, as a prerequisite to dealing adequately and in an insightful way with the production and perception of spontaneous speech.

Humans↗
PubMedDate not supplied

A paradigm to measure mismatch negativity responses to phonetic and acoustic changes in parallel.

The mismatch negativity (MMN) of the event-related potential has been purported to be an objective index of central auditory processing. The present study tested a new paradigm to measure the MMN responses to phonological changes in parallel with those to simple acoustic changes. Stimulus sequences consisted of repetitive consonant-vowel syllables interspersed with infrequent phonetic changes (in place of articulation or voicing) and repetitive sinusoidal tones with occasional acoustic changes (in frequency or duration). The speech and tone stimuli were delivered to the opposite ears (right and left, respectively) at a stimulus onset asynchrony (SOA) of 300 ms. The MMNs elicited in this new paradigm were compared with those measured in a conventional paradigm, in which the speech and tone stimuli were presented in separate sequences at an identical speech-speech or tone-tone SOA (600 ms) of the new paradigm. The MMNs elicited in the two paradigms had a similar morphology and topography, although the MMNs measured with the new paradigm were slightly smaller for 3 out of 4 types of deviants. The results suggest that the new paradigm enables the measurement of reliable MMNs to phonetic changes in parallel with those to acoustic changes.

Adult↗