Using ultrasound tongue imaging to identify covert contrasts in children’s speech

Abstract

Ultrasound tongue imaging has become a promising technique for detecting covert contrasts, due to the developments in data analysis methods that allow for processing information on tongue shape from young children. An important feature concerning analyses of ultrasound data from children who are likely to produce covert contrasts is that the data are likely to be collected without head-to-transducer stabilisation, due to the speakers' age. This article is a review of the existing methods applicable in analysing data from non-stabilised recordings. The article describes some of the challenges of ultrasound data collection from children, and analysing these data, as well as possible ways to address those challenges. Additionally, there are examples from typical and disordered productions featuring covert contrasts, with illustrations of quantifying differences in tongue shape between target speech sounds.

An Ultrasound Study of the Development of Lingual Coarticulation during Childhood

“…While the obvious advantage of such Zharkova measures is that they can be used with very young children, their limitation is that they may not be as powerful as the measurements based on the whole tongue contour (see a discussion in Zharkova et al, 2017). This may have been the reason why the difference between consonant contours conditioned by contrasting vocalic environments was not captured for /ʃ/ by LOC a-i in any age group, and also for the lack of significant differences in the magnitude of effect on curvature degree across lingual consonants in most age groups.…”

“…One of the challenges in this task was ensuring the reliability of quantitative comparisons of tongue contours across age groups, which required recording the same stimuli from all children. In order to keep the data collection procedure maximally ecologically valid for all age groups, the elicitation procedures differed across groups, taking into account age-related psychological differences, as well as the challenges involved with collecting articulatory data from young children (see Zharkova et al, 2017). For recording sufficient numbers of repetitions from the youngest participants, the optimal procedure was found to be repeating after the child's carer.…”

“…Video recordings of the 2 youngest groups were qualitatively examined in order to establish whether the tokens were suitable for quantitative analyses of tongue shape (see Zharkova et al, 2017, on the methodological challenges of analysing ultrasound data recorded without head stabilisation). In the tokens that were included, the ultrasound transducer was relatively stable under the chin during the target syllable, with the tongue curve flanked by the shadows of the chin and of the hyoid bone (see an example in Fig.…”

Padrões silábicos no desenvolvimento fonológico típico e atípico: análise ultrassonográfica

“…Although the acoustic studies have promoted an advance in relation to the phonetic detailing of children's productions, the acoustic information is capable of performing only articulatory inferences. In this sense, methodologies that make use of articulatory instruments (electropalatography, micro X-rays, ultrasonography, articulography) have gained space, since they allow the direct visualization of speech-articulatory organs during speech production (13)(14)(15)(16)(17) .…”

Ultrasound Images of the Tongue: A Tutorial for Assessment and Remediation of Speech Sound Errors

“…Ultrasound imaging may also be useful diagnostically, e.g., to characterize errors in lingual shapes, 26,27 , or to identify sub-perceptible or covert contrasts in disordered speech 28,29 . If precise articulatory measurements are being obtained and compared, it is essential that the ultrasound be stabilized so that the coordinate space for measurement remains reasonably constant.…”