Sex-specific fundamental and formant frequency patterns in a cross-sectional study

An extensive developmental acoustic study of the speech patterns of children and adults was reported by Lee and colleagues [Lee et al., J. Acoust. Soc. Am. 105, 1455-1468 (1999)]. This paper presents a reexamination of selected fundamental frequency and formant frequency data presented in their report for 10 monophthongs by investigating sex-specific and developmental patterns using two different approaches. The first of these includes the investigation of age- and sex-specific formant frequency patterns in the monophthongs. The second, the investigation of fundamental frequency and formant frequency data using the critical band rate (bark) scale and a number of acoustic-phonetic dimensions of the monophthongs from an age- and sex-specific perspective. These acoustic-phonetic dimensions include: vowel spaces and distances from speaker centroids; frequency differences between the formant frequencies of males and females; vowel openness/closeness and frontness/backness; the degree of vocal effort; and formant frequency ranges. Both approaches reveal both age- and sex-specific development patterns which also appear to be dependent on whether vowels are peripheral or non-peripheral. The developmental emergence of these sex-specific differences are discussed with reference to anatomical, physiological, sociophonetic and culturally determined factors. Some directions for further investigation into the age-linked sex differences in speech across the lifespan are also proposed

Lingual articulation in children with developmental speech disorders

This thesis presents thirteen research papers published between 1987-97, and a summary and discussion of their contribution to the field of developmental speech disorders. The publications collectively constitute a body of work with two overarching themes. The first is methodological: all the publications report articulatory data relating to tongue movements recorded using the instrumental technique of electropalatography (EPG). The second is the clinical orientation of the research: the EPG data are interpreted throughout for the purpose of informing the theory and practice of speech pathology. The majority of the publications are original, experimental studies of lingual articulation in children with developmental speech disorders. At the same time the publications cover a broad range of theoretical and clinical issues relating to lingual articulation including: articulation in normal speakers, the clinical applications of EPG, data analysis procedures, articulation in second language learners, and the effect of oral surgery on articulation. The contribution of the publications to the field of developmental speech disorders of unknown origin, also known as phonological impairment or functional articulation disorder, is summarised and discussed. In total, EPG data from fourteen children are reported. The collective results from the publications do not support the cognitive/linguistic explanation of developmental speech disorders. Instead, the EPG findings are marshalled to build the case that specific deficits in speech motor control can account for many of the diverse speech error characteristics identified by perceptual analysis in previous studies. Some of the children studied had speech motor deficits that were relatively discrete, involving, for example, an apparently isolated difficulty with tongue tiplblade groove formation for sibilant targets. Articulatory difficulties of the 'discrete' or specific type are consistent with traditional views of functional lingual articulation in developmental speech disorders articulation disorder. EPG studies of tongue control in normal adults provided insights into a different type of speech motor control deficit observed in the speech of many of the children studied. Unlike the children with discrete articulatory difficulties, others produced abnormal EPG patterns for a wide range of lingual targets. These abnormal gestures were characterised by broad, undifferentiated tongue-palate contact, accompanied by variable approach and release phases. These 'widespread', undifferentiated gestures are interpreted as constituting a previously undescribed form of speech motor deficit, resulting from a difficulty in controlling the tongue tip/blade system independently of the tongue body. Undifferentiated gestures were found to result in variable percepts depending on the target and the timing of the particular gesture, and may manifest as perceptually acceptable productions, phonological substitutions or phonetic distortions. It is suggested that discrete and widespread speech motor deficits reflect different stages along a developmental or severity continuum, rather than distinct subgroups with different underlying deficits. The children studied all manifested speech motor control deficits of varying degrees along this continuum. It is argued that it is the unique anatomical properties of the tongue, combined with the high level of spatial and temporal accuracy required for tongue tiplblade and tongue body co-ordination, that put lingual control specifically at risk in young children. The EPG findings question the validity of assumptions made about the presence/absence of speech motor control deficits, when such assumptions are based entirely on non-instrumental assessment procedures. A novel account of the sequence of acquisition of alveolar stop articulation in children with normal speech development is proposed, based on the EPG data from the children with developmental speech disorders. It is suggested that broad, undifferentiated gestures may occur in young normal children, and that adult-like lingual control develops gradually through the processes of differentiation and integration. Finally, the EPG fmdings are discussed in relation to two recent theoretical frameworks, that of psycho linguistic models and a dynamic systems approach to speech acquisition

Phonological category quality in the mental lexicon of child and adult learners

• Aims and Objectives: The aim was to identify which criteria children used to decide on the category membership of native and non-native vowels, and to get insight into the organization of phonological representations in the bilingual mind. • Methodology: The study consisted of two cross-language mispronunciation detection tasks, in which L2 vowels were inserted in L1 words, and vice versa. In Experiment 1, 9-12-year-old Dutch-speaking children were presented with Dutch words which were either pronounced with the target Dutch vowel or with an English vowel inserted in the Dutch consonantal frame. Experiment 2 was a mirror of the first, with English words which were pronounced ‘correctly’ or which were ‘mispronounced’ with a Dutch vowel. • Data and Analysis: It was examined to what extent child and adult listeners accepted substitutions of Dutch vowels by English ones, and vice versa, and which vowel substitutions were accepted or rejected. • Findings: The results of Experiment 1 revealed that at that age children have well-established phonological vowel categories in their native language. However, Experiment 2 showed that in the non-native language, children tended to accept mispronounced items which involve sounds from their native language. At the same time, though, they did fully rely on their native phonemic inventory because the children accepted most of the correctly pronounced English items. • Originality: While many studies have examined native and non-native perception by infants, studies on first and second language perception of school-age children are rare. This study adds to the body of literature aimed at expanding our knowledge in this area. • Implications: The study has implications for models of the organization of the bilingual mind: while proficient adult non-native listeners generally have clearly separated sets of phonological representations for their two languages, for non-proficient child learners, the L1 phonology still exerts a big influence on the L2 phonology

A Vowel Analysis of the Northwestern University-Children\u27s Perception of Speech Evaluation Tool

In an analysis of the speech perception evaluation tool, the Northwestern University – Children’s Perception of Speech test, the goal was to determine whether the foil words and the target word were phonemically balanced across each page of test Book A, as it corresponds to the target words presented in Test Form 1 and Test Form 2 independently. Based on vowel sounds alone, variation exists in the vowels that appear on a test page on the majority of pages. The corresponding formant frequencies, at all three resonance levels for both the average adult male speaker and the average adult female speaker, revealed that the target word could be easily distinguished from the foil words on the premise of percent differences calculated between the formants of the target vowel and the foil vowels. For the population of children with hearing impairments, especially those with limited or no access to the high frequencies, the NU-CHIPS evaluation tool may not be the best indicator of the child’s speech perception ability due to significant vowel variations

Developmental trends in voice onset time: some evidence for sex differences

This study reports on an investigation into the voice onset time (VOT) patterns of the plosives /p b t d/ in a group of 30 children aged 7 (n = 10), 9 (n = 10) and 11 (n = 10) years. Equal numbers of girls and boys participated in the study. Each child named a series of letter objects to elicit /p b t d/ in a syllable onset position with a fixed vowel context. VOT data were examined for age, sex and plosive differences with the following hypotheses: Firstly, that there would be sex differences in the VOT patterns of preadolescent children. Secondly, that the sex differences in VOT patterns would be linked to age and development, and that these would eventually become marked by the age of 11 years, by which time adult-like VOT values should have been achieved. Finally, that the extent of sex and age differences would be dependent upon the plosive being investigated. Results indicated patterns of decrease with age in the VOT values of /p b/ for the boys, with some evidence of increases in the VOT values of /t/ for the girls. In addition, 'voiced' and 'voiceless' cognates showed a more marked bimodal distribution in the girls' VOT patterns. This bimodal distribution was investigated by examining the degree of difference between the VOT values of voiced and voiceless cognate pairs /p b/ and /t d/, and examining the effects of age, sex and cognate pair. These results indicated that more marked sex differences in the 'voiced'/'voiceless' contrast emerged between the data of the 9- and 11-year-olds, a pattern, which was more marked for the alveolar plosives. These preliminary results confirmed all three hypotheses. The findings are presented and discussed both within a developmental and sociophonetic framework

Developmental trends in voice onset time: some evidence for sex differences

This study reports on an investigation into the voice onset time (VOT) patterns of the plosives /p b t d/ in a group of 30 children aged 7 (n = 10), 9 (n = 10) and 11 (n = 10) years. Equal numbers of girls and boys participated in the study. Each child named a series of letter objects to elicit /p b t d/ in a syllable onset position with a fixed vowel context. VOT data were examined for age, sex and plosive differences with the following hypotheses: Firstly, that there would be sex differences in the VOT patterns of preadolescent children. Secondly, that the sex differences in VOT patterns would be linked to age and development, and that these would eventually become marked by the age of 11 years, by which time adult-like VOT values should have been achieved. Finally, that the extent of sex and age differences would be dependent upon the plosive being investigated. Results indicated patterns of decrease with age in the VOT values of /p b/ for the boys, with some evidence of increases in the VOT values of /t/ for the girls. In addition, 'voiced' and 'voiceless' cognates showed a more marked bimodal distribution in the girls' VOT patterns. This bimodal distribution was investigated by examining the degree of difference between the VOT values of voiced and voiceless cognate pairs /p b/ and /t d/, and examining the effects of age, sex and cognate pair. These results indicated that more marked sex differences in the 'voiced'/'voiceless' contrast emerged between the data of the 9- and 11-year-olds, a pattern, which was more marked for the alveolar plosives. These preliminary results confirmed all three hypotheses. The findings are presented and discussed both within a developmental and sociophonetic framework

Correlating ASR Errors with Developmental Changes in Speech Production: A Study of 3-10-Year-Old European Portuguese Children's Speech

International audienceAutomatically recognising children's speech is a very difficult task. This difficulty can be attributed to the high variability in children's speech, both within and across speakers. The variability is due to developmental changes in children's anatomy, speech production skills et cetera, and manifests itself, for example, in fundamental and formant frequencies, the frequency of disfluencies, and pronunciation quality. In this paper, we report the results of acoustic and auditory analyses of 3-10-year-old European Portuguese children's speech. Furthermore, we are able to correlate some of the pronunciation error patterns revealed by our analyses - such as the truncation of consonant clusters - with the errors made by a children's speech recogniser trained on speech collected from the same age group. Other pronunciation error patterns seem to have little or no impact on speech recognition performance. In future work, we will attempt to use our findings to improve the performance of our recogniser

Automatically Recognising European Portuguese Children's Speech

International audienceThis paper reports findings from an analysis of errors made by an automatic speech recogniser trained and tested with 3-10-year-old European Portuguese children's speech. We expected and were able to identify frequent pronunciation error patterns in the children's speech. Furthermore, we were able to correlate some of these pronunciation error patterns and automatic speech recognition errors. The findings reported in this paper are of phonetic interest but will also be useful for improving the performance of automatic speech recognisers aimed at children representing the target population of the study

Speech characteristics of monozygotic twins and a same-sex sibling: an acoustic case study of coarticulation patterns in read speech

This case study reports on an acoustic investigation of the motor speech characteristics of a set of young adult male monozygotic (MZ) twins and compares them to those of an age- and sex-matched sibling who participated in the study 2 years later to match for demographic factors. Coarticulation patterns were investigated from read samples of consonant-vowel sequences in monosyllabic words containing a variety of consonants and vowels. This was done by examining F2 vowel onsets and F2 vowel targets, plotted as F2 locus equations. Data were processed for between-sibling differences using a number of statistical tests. Results indicated that the MZ twins displayed F2 parameters and coarticulation patterns which were more similar than those of their age- and sex-matched sibling. The results of this case study therefore suggest that acoustic phonetic parameters used to index coarticulation patterns have the potential to profile some of the similarities and differences in the speech characteristics of genetically related individuals

An acoustic investigation of the developmental trajectory of lexical stress contrastivity in Italian

We examined whether typically developing Italian children exhibit adult-like stress contrastivity for word productions elicited via a picture naming task (n=25 children aged 3\u20135 years and 27 adults). Stimuli were 10 trisyllabic Italian words; half began with a weak\u2013strong (WS) pattern of lexical stress across the initial 2 syllables, as in patata, while the other half began with a strong\u2013weak (SW) pattern, as in gomito. Word productions that were identified as correct via perceptual judgement were analysed acoustically. The initial 2 syllables of each correct word production were analysed in terms of the duration, peak intensity, and peak fundamental frequency of the vowels using a relative measure of contrast\u2014the normalised pairwise variability index (PVI). Results across the majority of measures showed that children\u2019s stress contrastivity was adult-like. However, the data revealed that children\u2019s contrastivity for trisyllabic words beginning with a WS pattern was not adult-like regarding the PVI for vowel duration: children showed less contrastivity than adults. This effect appeared to be driven by differences in word-medial gemination between children and adults. Results are compared with data from a recent acoustic study of stress contrastivity in English speaking children and adults and discussed in relation to language-specific and physiological motor-speech constraints on production