Spatial and Temporal Lingual Coarticulation and Motor Control in Preadolescents

Abstract

PURPOSE In this study, the authors compared coarticulation and lingual kinematics in preadolescents and adults in order to establish whether preadolescents had a greater degree of random variability in tongue posture and whether their patterns of lingual coarticulation differed from those of adults. METHOD High-speed ultrasound tongue contour data synchronized with the acoustic signal were recorded from 15 children (ages 10-12 years) and 15 adults. Tongue shape contours were analyzed at 9 normalized time points during the fricative phase of schwa-fricative-/a/ and schwa-fricative-/i/ sequences with the consonants /s/ and /ʃ/. RESULTS There was no significant age-related difference in random variability. Where a significant vowel effect occurred, the amount of coarticulation was similar in the 2 groups. However, the onset of the coarticulatory effect on preadolescent /ʃ/ was significantly later than on preadolescent /s/, and also later than on adult /s/ and /ʃ/. CONCLUSIONS Preadolescents have adult-like precision of tongue control and adult-like anticipatory lingual coarticulation with respect to spatial characteristics of tongue posture. However, there remains some immaturity in the motor programming of certain complex tongue movements.

Spectral dynamics of sibilant fricatives are contrastive and language specific

“…The decision to analyze temporal variation in peak frequency relative to proportional duration was made in order to maintain methodological consistency with previous studies that also analyzed the acoustic and articulatory dynamics of sibilants relative to proportional duration (e.g., Iskarous et al, 2011;Koenig et al, 2013;Zharkova et al, 2014); however, there is the worry that some of the apparent differences between the peak ERB N number trajectories of two sibilants may have arisen as artifacts of the normalization to proportional time. For example, one consequence of normalizing each production to proportional time is that as the duration of a production decreased, the overlap between adjacent analysis windows increased.…”

“…The generation of noise sources, therefore, involves the tongue and jaw since these articulators, respectively, form the constriction and position the lower incisors. Furthermore, articulatory studies of sibilant fricatives have found that the tongue and jaw both move continuously during their production (e.g., Iskarous et al, 2011;Mooshammer et al, 2006;Zharkova et al, 2014).…”

An Ultrasound Study of the Development of Lingual Coarticulation during Childhood

“…In particular, lingual coarticulation has been demonstrated to be present since at least the age of 2 years (Goodell and Studdert-Kennedy, 1993). And yet, the development of lingual coarticulation has been shown to be protracted, with certain non-adult-like patterns observed in children up to 12 years old (e.g., Zharkova et al, 2014). A growing number of studies have also shown that coarticulation development is segment-specific (Katz and Bharadwaj 2001;Zharkova et al, 2012Zharkova et al, , 2014Reidy, 2015).…”

“…And yet, the development of lingual coarticulation has been shown to be protracted, with certain non-adult-like patterns observed in children up to 12 years old (e.g., Zharkova et al, 2014). A growing number of studies have also shown that coarticulation development is segment-specific (Katz and Bharadwaj 2001;Zharkova et al, 2012Zharkova et al, , 2014Reidy, 2015). There is, however, very little information on the developmental course of segment-specific lingual coarticulatory patterns throughout childhood (see, e.g., Rubertus et al, 2015;Zharkova, 2017).…”

“…Both these theories are compatible with the premise that children's productions are limited by their general motor abilities, which undergo continuous development during childhood. Such protracted maturation of speech motor abilities, in particular, has been demonstrated in a number of acoustic and articulatory studies (e.g., Smith and Goffman, 1998;Walsh and Smith, 2002;Koenig et al, 2008;Zharkova et al, 2011Zharkova et al, , 2012Romeo et al, 2013;Zharkova et al, 2014). For the children in their first 2 years of life, the dependence of speech production on developing motor skills has been formulated in terms of language-specific "opportunities and challenges" (Vihman, 2010, p. 279), which enhance or inhibit, respectively, the likelihood of children's phonetic realisations corresponding to adult targets (see also Vihman, 2014).…”