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PubMed1982

Coarticulation effects in lipreading.

Normal-hearing and hearing-impaired subjects with good lipreading skills lipread videotaped material under visual-only conditions. V1CV2 utterances were used where V could be /i/, /ae/ or /u/ and C could be /p/, /t/, /k/, /ch/, /f/, /theta/, /sh/, /sh/ or /w/. Coarticulatory effects were present in these stimuli. The influence of phonetic context on lipreading scores for each V and C was analyzed in an effort to explain some of the variability in the visual perception of phonemes which was suggested by existing literature. Transmission of information for four phonetic features was also analyzed. Lipreading performance was nearly perfect for /p/, /f/, /w/, /theta/ and /u/. Lipreading performance on /t/, /k/, /ch/, /s/, /i/ and /ae/ depended on context. The features labial, rounded, and alveolar or palatal place of articulation were found to transmit more information to lipreaders than did the feature continuant. Variability in articulatory parameters resulting from coarticulatory effects appears to increase overall lipreading difficulty.

Correction of Hearing Impairment↗
PubMed1985

Vocal/verbal response times of normal-hearing and hearing-impaired children.

A series of experiments are reported that contrast vocal/verbal reaction-time measures from 16 normal-hearing and 25 hearing-impaired children 7 to 14 years old. Sixteen of the hearing-impaired children were enrolled in a residential school, 9 in a day school. Vocal reaction time of the children in response to visually presented stimuli was measured in four tasks: phonating "uh", saying the word "one", counting to digits, and naming digits. No significant differences were found between the response latencies of the two hearing-impaired groups on any task. Nor were differences found between the normal and hearing-impaired groups when the task was simply phonating "uh". Differences between these groups began to emerge when the word "one" was spoken. These differences increased systematically with the phonetic complexity of the task. Hearing level, latency in the counting responses, and magnitude of a ratio between phonating and digit counting latencies were identified as major predictors of speech intelligibility. The results suggest that central phonetic processing functions may be related to the quality of speech production by hearing-impaired talkers.

Adolescent↗
PubMed1988

Perceptual categorization and consistency of synthesized (r-w) continua by adults, normal children and (r)-misarticulating children.

The purpose of this study was to determine if children who misarticulate (r) differ from normal children and adults in the perception of sound features that are produced correctly and incorrectly. Children with normal articulation, children who produced (r) misarticulations, and adults listened to synthesized child and adult (r-w) continua in two separate sessions, and to an adult (b-w) control continuum in one session. Perception was evaluated on the basis of measures of phonetic boundary location and the consistency of response to each stimulus in a continuum. The (r)-misarticulating children were found to be significantly less consistent than child and adult controls in responding to the (r-w) stimuli. Moreover, consistency scores were significantly higher for the adult continuum than for the child continuum. The performance of children was different from that of adults. Due to inconsistent performance, boundaries could not be computed for (r)-misarticulating children, but it was found that the boundaries for children in the control group were closer to the (r)-end of the continuum than those for adults. In the case of the (b-w) continuum, it was found that (r)-misarticulating children were significantly less consistent than adults. The phonetic boundaries of children were significantly closer to the (b)-end of the continuum than the boundary for adults. Thus, the results reveal that variability in stimulus response was influenced primarily by the productive ability of the subjects, whereas differences in stimulus categorization were influenced by the age of the subjects. The perceptual variability was most clearly reflected by responses to stimuli produced incorrectly, whereas categorization differences extended to sounds produced correctly.

Adult↗
PubMed1989

Analysis of language-speech samples with salt and pepper.

Microcomputer-aided analysis of spontaneous language-speech samples offers researchers an efficient means of analyzing large amounts of data. It may be necessary, however, to format samples for more than one software program in order to obtain comprehensive morpho-syntactic and phonetic/phonologic analyses. This paper suggests a procedure for the combined use of SALT (Systematic Analysis of Language Transcripts, Miller & Chapman, 1985) and PEPPER (Programs to Examine Phonetic and Phonologic Evaluation Records, Shriberg, 1986) that is designed to minimize the duplication of effort involved in following two different formatting procedures. Results of a study undertaken to explore methodological issues in the combined use of SALT and PEPPER generally support the validity, reliability, and efficiency of the procedure. Results also raise some issues concerning the use of narrow phonetic transcription as opposed to standard orthographic transcription of continuous language-speech samples.

Data Collection↗
PubMed1992

Quantitative description of the dysarthria in women with amyotrophic lateral sclerosis.

Speech intelligibility and its phonetic and acoustic correlates were studied in a group of 10 women with amyotrophic lateral sclerosis (ALS). Intelligibility assessment with a word-identification test indicated that the most disrupted phonetic features pertained to velopharyngeal valving, lingual function for consonant contrasts of place and manner, and syllable shape. An acoustic signature analysis based on trajectories of the first and second formants in selected monosyllabic test words revealed that the mean slope of the second formant (F2) was reduced compared with that of a normal geriatric control group. This F2 slope reduction is interpreted to reflect loss of lingual motoneurons. Acoustic measures of phonatory function for sustained vowel prolongation demonstrated abnormalities in fundamental frequency, perturbations of frequency (jitter) and amplitude (shimmer), and signal-to-noise ratio. The data for women with ALS are compared with data for a normal geriatric control group of women and with data for a group of 25 men with ALS (Kent et al., 1990). Although the overall ranking of errors was similar for males and females with ALS, men were more likely to have impairments of voicing in syllable-initial position.

Adult↗
PubMed1992

Locus equations as an index of coarticulation for place of articulation distinctions in children.

Locus equations were investigated as a phonetic index for children's production of stop + vowel tokens. Locus equations are straight-line regression fits to data points formed by plotting onsets of F2 transitions along the ordinate and their corresponding midvowel nuclei along the abscissa. Such functions for adult speech have been found to be extremely linear with slope and y-intercept values contrastively distinctive across place of articulation. Sixteen children, aged 3-5 years, produced /bVt/, /dVt/, and /gVt/ tokens embedded in a carrier phrase and repeated in randomized order a minimum of three times. Six medial vowel contexts were used [i, I, ae, [symbol: see text], a, u]. Both individual and group mean scatterplots were extremely linear and highly remniscent of adult prototypes. While labial and velar slopes exhibited some degree of overlap, labial versus alveolar and alveolar versus velar slopes were significantly different. All y-intercepts as a function of place of articulation were significantly different. Compared to adult norms, intersubject variability of slope and y-intercept ranges were greater for children. Locus equations can provide a phonetic descriptor for a child's attainment of stop place categories seeking to achieve the adult standard of a balance between coarticulatory adjustments and contrastive distinctiveness.

Child Development↗
PubMed1993

The emergence of mature gestural patterns is not uniform: evidence from an acoustic study.

Previous studies investigating the organization of articulatory gestures present conflicting accounts of age-related differences in the execution of the articulatory gestures themselves and in the organization of those gestures. Several methodological differences may help to explain these contradictions: First, different studies have used different measures, all of which reflect vocal-tract activity to varying extents; second, the articulatory gestures being analyzed differed across studies; third, the phonetic composition of syllables has varied; and finally, utterance length, and therefore complexity, has varied across studies. The purpose of this study was to investigate the possibility that the reason these methodological differences have led to contradictory results is because the emergence of mature gestural patterns in children's speech is not uniform. To accomplish this goal, detailed acoustic analyses were performed on schwa-stop-vowel utterances from adults and from children (3, 5, and 7 years of age). Temporal measures showed that some acoustic segments were longer in children's than in adults' samples, whereas others were similar in duration. Formant frequencies indicated that vocal-tract opening and closing achieve adult-like patterns of movement by the age of 3 years, but children's tongue gestures are constrained by phonetic context more than those of adults until at least the age of 7 years. Taken together, these results suggest that the pace of development for learning to produce and to coordinate articulatory gestures is not uniform. Thus, the contradictions in findings among earlier studies may very well reflect differences in choices of measurement and utterances to be analyzed, both of which may lead to evaluations of different aspects of gestural patterning.

Adult↗
PubMed1996

The specific relation between perception and production errors for place of articulation in developmental apraxia of speech.

Developmental apraxia of speech is a disorder of phonological and articulatory output processes. However, it has been suggested that perceptual deficits may contribute to the disorder. Identification and discrimination tasks offer a fine-grained assessment of central auditory and phonetic functions. Seventeen children with developmental apraxia (mean age 8:9, years:months) and 16 control children (mean age 8:0) were administered tests of identification and discrimination of resynthesized and synthesized monosyllabic words differing in place-of-articulation of the initial voiced stop consonants. The resynthetic and synthetic words differed in the intensity of the third formant, a variable potentially enlarging their clinical value. The results of the identification task showed equal slopes for both subject groups, which indicates no phonetic processing deficit in developmental apraxia of speech. The hypothesized effect of the manipulation of the intensity of the third formant of the stimuli was not substantiated. However, the children with apraxia demonstrated poorer discrimination than the control children, which suggests affected auditory processing. Furthermore, analyses of discrimination performance and articulation data per apraxic subject demonstrated a specific relation between the degree to which auditory processing is affected and the frequency of place-of-articulation substitutions in production. This indicates the interdependence of perception and production. The results also suggest that the use of perceptual tasks has significant clinical value.

Apraxias↗
PubMed1999

Do temporal processing deficits cause phonological processing problems?

This study tested the hypothesis that temporal processing deficits underlie phonological processing problems. The subjects were children aged 8 to 10 years (N = 110) who were separated into 2 groups on the basis of whether their reading scores were normal or poor. As predicted by many earlier studies, children with poor reading scores demonstrate poor abilities on tests of phonological awareness, as well as on 2 other language tasks that depend on phonological processing. Two specific tests of the temporal processing hypothesis were conducted. Children in both groups were tested (a) on their abilities to recall sequences of nonspeech tones presented at various rates and (b) on their abilities to make phonetic decisions using brief and transitional properties of the speech signal, especially formant transitions (the purported "trouble spot" in the speech signal for children with phonological processing problems). The children with poor phonological processing abilities showed no special difficulty recalling rapidly presented nonspeech stimuli, and, in their phonetic decisions, they were able to use brief and transitional signal properties, including formant transitions, at least as well as other children. Therefore, no evidence was found to support the hypothesis that temporal processing deficits cause phonological processing problems.

Awareness↗
PubMed1999

Speech perception and verbal memory in children with and without histories of otitis media.

Two groups of children, with (n = 7) and without (n = 7) first-year histories of otitis media, were participants in a longitudinal study that included periodic audiological and medical evaluations during the first year of life. At age 9, these children were tested on a series of speech perception and verbal short-term memory tasks using stimuli of varying degrees of phonetic contrast. Although the otitis-positive group performed less accurately than the otitis-free group, the pattern of errors was the same for the two groups. The performances of the children with and without positive histories of otitis media were negatively affected by an increase in phonetic similarity of the stimulus items. The two groups, however, did not differ on identification or on temporal-order recall when the speech sounds were differentiated by multiple features. These findings provide evidence of subtle, long-term effects of early episodes of otitis media on phonological representations and on working memory.

Child↗
PubMed2001

Patient evaluation of treatment with fixed implant-supported partial dentures.

The aim of this study was to analyse the patient evaluation of functional treatment outcome in 40 periodontally compromised patients who received implant-supported prostheses (ISPs) as part of the total treatment. The treatment protocol comprised periodontal treatment, extraction of teeth with poor prognosis, placement of dental titanium implants, and after healing, insertion of fixed ISPs. Five of the patients became edentulous in one jaw after extraction of all teeth and received a complete ISP, whereas 35 patients became partially edentulous after extraction of some teeth, 12 receiving a partial ISP on > or = 3 implants, and 23 one on two implants. The follow-up period was on average 1.8 years after the connection of the prostheses, which provided the patients a dentition with a mean of 12 occluding dental units. The first author (S.-W. Yi) performed all implant treatment. Patients' opinions on oral functions--mastication, phonetics, oral hygiene, chewing comfort and aesthetics--were evaluated by means of a questionnaire both before implant installation and at the last follow-up. A control group of 30 subjects with a healthy dentition of 14 occluding natural pairs of teeth answered the same questionnaire on one occasion. A great majority of the patients were extremely satisfied with the oral function after treatment and experienced the ISPs as 'natural teeth'. There was no significant difference between the three treatment groups and the control group for mastication, phonetics, chewing comfort and aesthetics. Patients with ISPs reported a small but significantly greater difficulty with oral hygiene procedures than the controls with natural teeth. Most patients said that they would undergo the treatment again, if necessary, and recommend it to others. It was concluded that the rehabilitation of the periodontally compromised patients, including ISPs on osseointegrated dental titanium implants, resulted in subjectively improved and satisfactory oral function.

Adult↗
PubMed2002

Phonotactic therapy.

Words derive their structure not only from the sounds they include but also from the organization of those sounds within the word. This organization is the phonotactic level of the word: roughly, its shape including the sequence of its elements. Often, children with immature or disordered phonologies demonstrate phonotactic as well as phonetic limitations. Sometimes, the child may produce an age-appropriate variety of consonants and vowels but be unable to use them in the configurations required by the language: final consonants, clusters, multisyllabic words, and so forth. In such cases, the most appropriate therapy goals may be phonotactic, rather than phonetic, ones. Studies have shown that clinical focus on a new word or syllable shape may generalize well beyond the specific sound or sounds targeted in that position. These ideas are explored in this article, along with specific therapy results and recommendations for various phonotactic limitations.

Child, Preschool↗
PubMed2006

Task-modulated "what" and "where" pathways in human auditory cortex.

Human neuroimaging studies suggest that localization and identification of relevant auditory objects are accomplished via parallel parietal-to-lateral-prefrontal "where" and anterior-temporal-to-inferior-frontal "what" pathways, respectively. Using combined hemodynamic (functional MRI) and electromagnetic (magnetoencephalography) measurements, we investigated whether such dual pathways exist already in the human nonprimary auditory cortex, as suggested by animal models, and whether selective attention facilitates sound localization and identification by modulating these pathways in a feature-specific fashion. We found a double dissociation in response adaptation to sound pairs with phonetic vs. spatial sound changes, demonstrating that the human nonprimary auditory cortex indeed processes speech-sound identity and location in parallel anterior "what" (in anterolateral Heschl's gyrus, anterior superior temporal gyrus, and posterior planum polare) and posterior "where" (in planum temporale and posterior superior temporal gyrus) pathways as early as approximately 70-150 ms from stimulus onset. Our data further show that the "where" pathway is activated approximately 30 ms earlier than the "what" pathway, possibly enabling the brain to use top-down spatial information in auditory object perception. Notably, selectively attending to phonetic content modulated response adaptation in the "what" pathway, whereas attending to sound location produced analogous effects in the "where" pathway. This finding suggests that selective-attention effects are feature-specific in the human nonprimary auditory cortex and that they arise from enhanced tuning of receptive fields of task-relevant neuronal populations.

Adaptation, Physiological↗
PubMed1989

Acoustic interference in a recognition task.

Phonetic or acoustic characteristics of stimuli in recall studies have consistently been shown to generate more interference over short intervals than semantic characteristics. We performed three experiments to determine whether this characteristic also applied to recognition processes over short intervals. Subjects were shown study lists of eight words and were asked to recognize which of those words recurred on subsequent eight-word lists. Delays varied from 0 to 100 s between study and test, with a rehearsal-preventing task inserted during the delays. Phonetic distractors generated greater interference than semantic distractors at all delay levels, and semantic distractors generated greater interference than random distractors. These distractor-type differences were not present in long-term recognition tasks. The deterioration in performance over time was considerably slower in these recognition experiments than in previous recall studies.

Adult↗
PubMedDate not supplied

Intervocalic consonants in the speech of typically developing children: emergence and early use.

The purpose of this paper is to present data on the development of intervocalic consonants in the first 2 years of life. The data address three different periods in the production of intervocalic consonants: babble, first words, and words from 21-24 months. The focus of analysis for all three data sets is on the phonetic properties of consonants in intervocalic position, and on comparisons of inventories across word-initial, intervocalic, and final position. For word productions, intervocalic inventories are compared to inventories for initial and final positions. Results of all three studies indicate that intervocalic consonants closely resemble initial consonants in terms of frequency of occurrence and phonetic features.

Age Factors↗
PubMedDate not supplied

The acquisition of medial /t, d/ allophones in bisyllabic contexts.

The acquisition of medial /t, d/ allophones was examined in four children between 2 and 5 years of age, over a period of 38 months. Children labelled pictures designed to elicit a sample of these allophones in iambic ([t]) and trochaic (flap, nasal and lateral release) contexts. Productions were analysed with reference to attainment of target allophones and use of non-target segmental (e.g., [d] or [t] in place of flap) and syllabic variants (e.g., unstressed syllable deletion). All children produced the target [t] allophone in iambic context. Across children, between 10 and 15 variants occurred in trochaic contexts. Nasal and lateral release allophones were never attained. Flap attainment was variable, with significant differences across children and across phonetic contexts. Results suggest a hierarchy of /t, d/ allophone production with reference to prosodic and phonetic contexts. Discussion includes implications of these findings for clinical intervention.

Child Language↗
PubMed2002

Feature development in Cantonese.

The phonetic inventories of 122 typically developing Cantonese-speaking children, aged from 0;10 to 4;7, were examined in terms of feature distinctions. The applicability of Dinnsen. Chin, Elbert and Powell's implicational feature hierarchy to these data was investigated. Results show that modifications to the hierarchy are necessary for the Cantonese phonetic system. A revised hierarchy for Cantonese is proposed. Differences between this proposal and the original work are discussed. The implicational nature of the proposed hierarchy was also tested on longitudinal data from ten children (aged from 0;10 to 3;5 at the beginning of the study) over a 1 year period. The proposed hierarchy successfully predicted the route of sound change of these inventories. Implications for further research on feature development are discussed.

Child Language↗
PubMedDate not supplied

A comparison of English reading passages for elicitation of speech samples from clinical populations.

Oral reading passages are often used to elicit speech samples from clinical populations. Few objective guidelines exist, however, to guide one's selection from among the many existing passages. Therefore, this study was undertaken to describe phonetic, lexical, and structural characteristics of 15 oral reading passages. The passages differed markedly in the demands that they placed upon the speaker (i.e., length and complexity), as well as the adequacy of the phonetic sample.

Humans↗