Sumalee Dechongkit

Lexical tones in Thai after unilateral brain damage

An acoustic perceptual investigation of the five lexical tones of Thai was conducted to evaluate the nature of tonal disruption in patients with unilateral lesions in the left and right hemisphere. Subjects (n = 48) included 10 young normal adults, 10 old normal adults, 11 right hemisphere nonaphasics, 9 left hemisphere fluent aphasics, and 8 left hemisphere nonfluent aphasics. The five Thai tones (mid, low, falling, high, rising) were produced in isolated monosyllables, presented for tonal identification judgments, and measured for fundamental frequency (Fo) and duration. Results of an analysis of variance indicated that left hemisphere nonfluent speakers signaled and tonal contrasts at a lower level of proficiency. The extent of their impairment varied depending on severity level of aphasia. When compared to normal speakers, tonal identification for less severe nonfluent aphasics differed more in degree than in kind, and for more severe nonfluent aphasics differed both in kind and in degree. Acoustic analysis revealed that with the exception of one left nonfluent, average Fo contours were comparable in shape across speaker groups. Variability in Fo production, however, was greater in left nonfluent speakers than in any of the other four groups of speakers. Issues are discussed regarding the extent and nature of tonal disruption in aphasia and hemispheric specialization for tone production.

Speech Timing at the Sentence Level in Thai After Unilateral Brain Damage

The present study examined temporal characteristics of spoken sentences in Thai to evaluate timing control in brain-damaged patients with unilateral left and right hemisphere lesions. Subjects included 10 young and 10 old normal adults, 14 right hemisphere patients, and 2 left hemisphere nonfluent and 7 fluent aphasic patients. Utterances were produced at a conversational speaking rate. Duration measures were taken from wide-band spectrograms. Results indicated that left hemisphere patients exhibited abnormal timing on both absolute and relative timing measures, whereas right hemisphere patients did not. Among left hemisphere patients, fluent as well as nonfluent aphasics exhibited aberrant temporal patterns. Left hemisphere patients were also more variable than right hemisphere patients which, in turn, were more variable than normals in their production of sentences. In comparison to earlier findings on timing at segment and word levels, it was found that deficit profiles varied between fluent and nonfluent aphasics as a function of the size of the linguistic unit with nonfluent aphasics being affected at the segment, word, and sentence level but fluent aphasics affected at the sentence level only. Findings are discussed in relation to issues pertaining to hemispheric specialization and the nature of timing deficits in nonfluent and fluent aphasic patients.

Speech prosody in affective contexts in Thai patients with right hemisphere lesions.

The production of speech prosody in emotional contexts was examined in Thai patients with unilateral right hemisphere damage. Twelve right hemisphere patients and nine normals read target sentences embedded in paragraphs that cued either a happy, sad, or neutral affect. Perceptual evaluations of their productions revealed a severe deficit in right hemisphere patients. Acoustic analysis indicated that longterm measures of fundamental frequency, timing, and energy at the sentence level were aberrant in right hemisphere patients. Findings are discussed in relation to nature and extent of prosodic deficits in right hemisphere patients, hemispheric specialization for linguistic and affective prosody, and the effect of language structure on the manifestation of affective prosody.

Factors Associated With Specific Language Impairment and Later Language Development During Early Life: A Literature Review

It has been reported that 50% of children with specific language impairment (SLI) have persistent SLI, which has been associated with various risk factors. To date, however, there has not been a comprehensive review of studies into different risk factors that could be used by clinicians to facilitate parental counseling and individual case-management. Several studies about the factors associated with SLI were reviewed based on study design. This article presents a review of factors associated with later language development and SLI, and reviews the risk for children who have SLI during early life. The summary provides data including specific biologic and environmental factors that are significantly associated with SLI, to ensure early intervention for children with SLI in the presence of identified risk factors.

Intraword timing relations in Thai after unilateral brain damage.

The present study examined temporal characteristics of monosyllabic, bisyallabic, and trisyllabic words in Thai to evaluate timing control at the word level in brain-damaged patients. Subjects included young and old normal adults, right hemisphere patients, and left hemisphere nonfluent and fluent aphasic patients. Utterances were produced at a conversational speaking rate. Results indicated that, on an absolute or relative measurement scale, magnitude of the shortening effect on nonfinal syllables in polysyllabic words was significantly smaller in left nonfluent aphasics than in other groups. In trisyllabic words, duration of the penultimate syllable for left fluent aphasics was also significantly longer than that of normals. Left nonfluent and fluent aphasics were significantly more variable than other speakers in their production of bisyllabic and trisyllabic words. Findings are discussed in relation to issues pertaining to the nature of timing deficits in nonfluent and fluent aphasic patients.

Timing characteristics of speech after brain damage: Vowel length in Thai ☆

This paper explores the extent of timing deficits in vowels produced by brain-damaged speakers of a language with a phonological contrast in vowel length. Short and long vowels in Thai were produced in isolated monosyllabic words by 20 normal adults, 14 right hemisphere patients, and 17 left hemisphere aphasics. Vowel durations were measured spectrographically. Although the phonological contrast was relatively preserved, as indicated by average duration, a subtle timing deficit in vowels produced by nonfluent aphasics was indicated by a compressed duration continuum and increased variability in vowel production.

Inter- and intraspeaker variability in fundamental frequency of Thai tones

Abstract A measure was obtained of variability in fundamental frequency ( F 0 ) in citation forms of lexical tones. The language selected for investigation was Thai, a tone language with five lexical tones: mid, low, falling, high and rising. Twenty speakers participited in the experiment: 10 “young” male speakers and 10 “old” speakers, 5 male and 5 female. High-quality tape recordings were obtained of each subjects productions of a minimal set of five monosyllabic words. F 0 contours were extracted by a cepstral analysis. A comparison was made of inter- and intraspeaker variability in the production of the five Thai tones. Results of analysis of variance indicated that the degree of intersubject variability in F 0 was greater than intraspeaker across all five tones, that young and old speakers exhibited the same pattern of variability, and that variability in tone production differed depending on the lexical tone. The falling and rising tones exhibited smaller degrees of variability than the mid, low or high. Findings are interpreted to highlight the nature of F 0 variability, the relationsip of F 0 variability to amount of F 0 movement, and crosslinguistic differences in F 0 variability as a function of prosodic structure.

Sequences of Phonemic Approximations in a Thai Conduction Aphasic

Sequences of phonemic approximations (SPAs) to a single target word on a picture naming task were investigated in a Thai-speaking conduction aphasic. A corpus of 207 SPAs was analyzed with an adaptation of Valdois, Joanette, and Nespoulouss (1989) methodology to a tone language. Measures included the length of SPAs, overall degree of approximation to the target of the last attempt and each of the preceding attempts, as well as degree of approximation to the target in terms of number of syllables, syllable structure, segments (consonants/vowels), and tones. Results indicated that there was a steady progression toward the target regardless of eventual outcome or length of sequence. Number of syllables of the target word was better preserved than syllable structure, and tones better than segments. In the course of SPAs, tonal information was accessed earlier than segmental, and syllabic length information earlier than syllabic structure. Within SPAs, tonal information was more stable than segmental across successive approximations. Findings are discussed in relation to a functional model of single word production and multidimensional phonological representations.

Tonal coarticulation in Thai after unilateral brain damage.

The magnitude and temporal extent of anticipatory and perseverative tonal coarticulation was investigated in Thai-speaking normal and brain-damaged adults. A total of 47 speakers (10 young normal, 10 old normal, 13 nonaphasic right-brain-damaged patients, 14 left-brain-damaged aphasic patients, 9 fluent, 5 nonfluent) produced all 25 possible sequences of two tones from the five lexical tones of Thai embedded in a carrier sentence. F0 contours were analyzed in terms of height and slope at 10% intervals throughout the duration of the two syllables. Acoustic analysis revealed that anticipatory and perseverative tonal coarticulation of tones was markedly reduced in left fluent aphasics, totally absent in left nonfluent aphasics, but reasonably intact in right hemisphere patients. Findings are interpreted to highlight the nature of speech disturbances in nonfluent and fluent aphasia, hemispheric specialization for tone, and tonal coarticulation in Thai.

Interaction between Tone and Intonation in Thai after Unilateral Brain Damage

Intonational characteristics of Thai sentences were used to evaluate fundamental frequency (F(0)) control in brain-damaged patients with unilateral left and right hemisphere lesions. Subjects (n = 41) included 9 young and 10 old normal adults, 12 right hemisphere patients, and 10 left hemisphere aphasic patients (7 fluent and 3 nonfluent). Sentences were comprised of six words, three of which were keywords occurring in sentence-initial, -medial, and -final positions. All 125 possible sequences of three of the five Thai tones (mid, low, falling, high, rising) were superimposed on monosyllabic keywords. Utterances were produced at a conversational speaking rate. Average F(0) of keywords was analyzed as a function of sentence position, tone, and group. For both normal and brain-damaged speakers, results indicated that tones in sentence-final position were significantly lower in F(0) than in either sentence-initial or -medial position; falling and high tones were significantly higher in F(0) than mid, low, and rising tones. Findings are discussed in relation to issues pertaining to hemispheric specialization and the nature of F(0) deficits in nonfluent and fluent aphasic patients.