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 397 records · Page 22Linked to original sources
PubMed1986

Topography of visual event-related potentials during geometric and phonetic discriminations.

Event-related potentials (ERPs) were obtained to letters during 3 tasks that involved a SIMPLE RESPONSE (SR) to each letter presentation, a FORM discrimination of the letters that formed a closed loop, and a RHYME discrimination of the letters that rhymed with the letter 'v'. The first task only required detection of the letters, the FORM task required a visual-spatial analysis, and the RHYME task, a grapheme-phoneme conversion of the letters followed by a determination of rhyming characteristics. The SR ERPs were morphologically different from the discriminative ERPs, notably by the absence of N2 and P3. The difference wave forms between the discrimination and SR conditions and between the targets and non-targets indicated differential topographies of components associated with the FORM and RHYME tasks in the 300 msec latency region. In both of these tasks, components exhibited distributions localized primarily in the occipital regions, whereas in the RHYME task they extended more anteriorly and encompassed temporo-parietal regions. Thus, although the stimulus presentation was visual, the requirement of a visual-auditory conversion in the RHYME task resulted in activity that was more proximal to auditory regions than when only a FORM analysis of the letters was required.

Adult↗
PubMed1978

Event-related brain potentials and selective attention to acoustic and phonetic cues.

N1 and P3 components of the human event-related potential were recorded from subjects performing a syllable discrimination task which required selective attention to one ear at a time. The N1 component was enhanced to all stimuli in the attended ear; while the P3 component was enhanced only to the "target" stimulus in that ear. The results are discussed in terms of hierarchical stages of selective attention.

Acoustic Stimulation↗
PubMed1987

Event-related brain potentials and the perception of a phonetic continuum.

Competing predictions concerning phoneme discrimination were tested by means of event-related potentials. In research on speech perception, one tradition stems from the physiology of the auditory system whereas another emphasizes categorical perception which involves a marked psychological component. The stimuli were the end points of the Finnish (i)-(y) continuum together with the intermediate boundary sound. Two of these stimuli were presented in each block of trials. One (the 'standard') had a high probability while the other (the 'deviant') was rare. The so-called mismatch negativity (MMN) component of the ERP in response to deviant stimuli showed a large amplitude and short latency when these two stimuli were pure vowels (i) and (y). When the boundary stimulus and one of the pure vowels comprised the stimulus pair, a smaller and more delayed MMN occurred. This result may be taken as support that the discrimination occurs at a basic physiological level. On the other hand, cognitive perception was reflected in the different latencies of the P3 component to (i) and (y). In sum, the results lend support to multilevel hybrid models in the explanation of vowel perception.

Adult↗
PubMed2005

Speech-sound duration processing in a second language is specific to phonetic categories.

The mismatch negativity (MMN) component of the auditory event-related potential was used to determine the effect of native language, Russian, on the processing of speech-sound duration in a second language, Finnish, that uses duration as a cue for phonological distinction. The native-language effect was compared with Finnish vowels that either can or cannot be categorized using the Russian phonological system. The results showed that the duration-change MMN for the Finnish sounds that could be categorized through Russian was reduced in comparison with that for the Finnish sounds having no Russian equivalent. In the Finnish sounds that can be mapped through the Russian phonological system, the facilitation of the duration processing may be inhibited by the native Russian language. However, for the sounds that have no Russian equivalent, new vowel categories independent of the native Russian language have apparently been established, enabling a native-like duration processing of Finnish.

Child↗
PubMed2002

Gradient effects of within-category phonetic variation on lexical access.

In order to determine whether small within-category differences in voice onset time (VOT) affect lexical access, eye movements were monitored as participants indicated which of four pictures was named by spoken stimuli that varied along a 0-40 ms VOT continuum. Within-category differences in VOT resulted in gradient increases in fixations to cross-boundary lexical competitors as VOT approached the category boundary. Thus, fine-grained acoustic/phonetic differences are preserved in patterns of lexical activation for competing lexical candidates and could be used to maximize the efficiency of on-line word recognition.

Eye Movements↗
PubMed2002

Speech perception deficits in Parkinson's disease: underestimation of time intervals compromises identification of durational phonetic contrasts.

Besides motor, vegetative, and cognitive signs, patients suffering from Parkinson's disease (PD) may show distinct perceptual deficits such as underestimation of time intervals extending across several seconds. Assuming this impairment also to affect the domain of tens of milliseconds, disrupted encoding of the acoustic speech signal with respect to segment durations conveying linguistic information must be expected. To test this hypothesis, 10 PD patients and matched controls performed an identification task using a series of 10 stimuli derived from the utterance "Boten" (/bo:tn/, 'messengers'; produced with nasal plosion) by exclusive manipulation of occlusion length (110-20 ms in steps of 10 ms). Under these conditions, word-medial silence cues the voicing category of the respective stop consonant. Seven PD subjects showed normal identification curves, i.e., categorized the shortest and longest stimuli with high probability each as the minimal pair cognates "Boden" and "Boten," respectively. In contrast, the remaining three patients labeled all items across the complete range of occlusion lengths as "Boden." A subsequent experiment found a horizontal shift of the identification curves toward larger signal durations (> 120 ms) in these three subjects. Bilateral cerebellar degeneration has been found to yield a different response pattern, i.e., near-chance level of performance. Considering recent information-processing models of scalar interval timing, striatal disorders seem to slow down an oscillatory pacemaker, whereas cerebellar dysfunctions may impair comparison of measured durations with stored reference memory traces.

Adult↗
PubMed2002

Asymmetrical mismatch negativity in humans as determined by phonetic but not physical difference.

A two-tone oddball procedure was employed to examine the effect of a phonemic category on the mismatch negativity (MMN). One of the stimuli was a phoneme prototype of Japanese /e/, and the other, [e/ö], which was perceived by Japanese participants as showing deviance from typicality but is nonetheless included in the category /e/. As control stimuli, a pair of pure tones (1940 and 1794 Hz), corresponding to the F2 frequencies of /e/ and [e/ö], respectively, was presented within the same oddball procedure. The MMN for deviant [e/ö] revealed greater amplitude than that of deviant /e/, although there was no significant difference in amplitude between the pure tones. The results suggest that a phonemic category determines the auditory sensory memory.

Acoustic Stimulation↗
PubMed2003

Language context and phonetic change detection.

Event-related brain potentials (ERP) were recorded to two spoken words, /paeti/ and /peti/. The vowel difference between the two words results in a semantical difference in Finnish, but not in Hungarian, in which /ae/ and /e/ are perceived as allophones of the same vowel /epsilon/. As a consequence, native Hungarian speakers, who had not studied Finnish before being tested, could not categorize the two word stimuli. In the main experiment, native Hungarian speakers, who fluently spoke Finnish, were presented with two oddball sequences in which /paeti/ was the frequent standard stimulus, /peti/ the infrequent deviant. In addition, very rare target words were also included. In one condition, the targets were Hungarian words, whereas in the other, they were Finnish words. The participants' sense of being in two different language environments was further encouraged by having separate experimenters conducting the two conditions, one speaking with the subjects only in Hungarian, the other only in Finnish. Language context had no effect on the mismatch negativity ERP component elicited by the deviant word stimuli. This result suggests that language context does not affect the pre-attentive detection of auditory deviance.

Adult↗