Patterns of variability in voice onset time: a developmental study of motor speech skills in humans

Abstract

This study investigated the developmental patterns of variability in the speech parameter voice onset time (VOT) in forty six children. Five groups of children participated in the study as follows: i) Group 1 -aged 5 years 8 months (n=6); ii) Group 2 -7 years 10 months (n=10); iii) Group 3 -9 years 10 months (n=10); iv) Group 4 -11 years 10 months (n=10), and v) Group 5 -13 years 2 months (n=10). Coefficient of variation (COV) values were examined for the VOT values of both "voiceless" (/p t k/) and "voiced" (/b d g/) plosives to determine patterns of variability. Significant effects of age were revealed for both the voiceless and voiced plosives, and levels of variability leveled off for Group 4. The data suggest that although variability in VOT decreases with age, the presence of residual variability may be a prerequisite for the further refinement of motor speech skills.

Objective measurement of motor speech characteristics in the healthy pediatric population

“…As expected, we found statistically significant increases in rates of diadochokinesis, second formant transitions, and standard syllabic rates with increasing age. The results from these voice and articulation parameters are consistent with numerous studies in the literature that demonstrate improved control of articulation with increasing age in children [8,9]. In 2008, Singh and Singh performed spectral-temporal analyses of syllabilicity, formant transitions, and place of articulation in 155 children between 4 and 8 years, with an equal number of boys and girls.…”

Voice onset time in Swedish children and adults

“…This is in line with the findings in studies of Englishspeaking children (Nittrouer 1993;Whiteside and Marshall 2001;Whiteside, Dobbin et al 2003).…”

“…The acquisition of adult-like VOTpatterns is gradual in the developing child. Several studies of English children display similar results regarding when this development is completed which seems to be around the age of 11 years, when stable adult-like VOT-values are observed (Nittrouer 1993;Whiteside and Marshall 2001;Whiteside, Dobbin and Henry, 2003). Larsson and Wiman, (2010) VOT is thought to reflect the co-ordination and timing between laryngeal and oral articulation.…”

Temporal variability in sung productions of adolescents who stutter

“…Previous studies report that children from 4 to 11 years show longer and more variable VOTs than adults (e.g., Yu et al, 2015). Older children and adolescents show more variable VOTs than adults, and decreases in variability are still observed until the age of 16 (Whiteside et al, 2003;Yu et al, 2015;Zlatin & Koenigsknecht, 1976). This time course in acquisition of VOT for voiceless stops is likely to be due to gestural reorganization during fluent speech development which includes processes that speed up gestural coordination, reduce overlap between adjacent consonant-vowel gestures and stabilize movement trajectories (e.g., Goffman & Smith, 1999;Goodell & StuddertKennedy, 1993;Nittrouer, 1993).…”

“…It has therefore been assessed in developmental studies as well as in studies of speech disorders (Auzou et al, 2000;Whiteside, Dobbin, & Henry, 2003;Yu et al, 2014;Yu, De Nil, & Pang, 2015). In particular, VOT variability has been discussed as a marker of fine-grained motor and timing control of oral and laryngeal processes.…”