Quantifying lingual coarticulation in German using mutual information: An ultrasound study

Abstract

In previous research, mutual information (MI) was employed to quantify the physical information shared between consecutive phonological segments, based on electromagnetic articulography data. In this study, MI is extended to quantifying coarticulatory resistance (CR) versus overlap in German using ultrasound imaging. Two measurements are tested as input to MI: (1) the highest point on the tongue body and (2) the first coefficient of the discrete Fourier transform (DFT) of the whole tongue contour. Both measures are used to examine changes in coarticulation between two time points during the syllable span: the consonant midpoint and the vowel onset. Results corroborate previous findings reporting differences in coarticulatory overlap in German and across languages. Further, results suggest that MI used with the highest point on the tongue body captures distinctions related both to place and manner of articulation, while the first DFT coefficient does not provide any additional information regarding global (whole tongue) as opposed to local (individual articulator) aspects of CR. However, both methods capture temporal distinctions in coarticulatory resistance between the two time points. Results are discussed with respect to the potential of MI measure to provide a way of unifying coarticulation quantification methods across data collection techniques.

Spoken Language Development and the Challenge of Skill Integration

“…We also anticipated consonantal effects on children's lingual coarticulatory patterns within each age cohort as found in a preceding study investigating children's intra-syllabic coarticulation from the age of 3 (Noiray et al, 2018). More specifically, we expected a lower degree of lingual coproduction for consonantvowel syllables requiring two constriction goals by spatially distinct articulatory organs than from those requiring two constriction goals by a single organ as found in adults (e.g., Iskarous et al, 2013;Abakarova et al, 2018), albeit to a lesser extent than adults. Importantly, expanding on previous research, we predicted greater phonological awareness and vocabulary would coincide with lower coarticulation degree, i.e., greater segmental differentiation of consonants and vowels in syllables.…”

“…Hence, children's vocalic and consonantal gestures may be activated more simultaneously than in adults, resulting in an overall larger vocalic influence on previous consonants and a greater degree of vocalic coarticulation than for adults. Instead, adults have been found to organize their speech with more temporally individuated gestures (Abakarova et al, 2018;Rubertus and Noiray, 2018). The result of rather large unit size speech organization echoes the multiple findings of wholeword learning (Vihman and Velleman, 1989;Keren-Portnoy et al, 2009;Menn and Vihman, 2011), transitional probability across syllables (e.g., Jusczyk et al, 1993;Saffran et al, 1996), or lexically grounded phonological development and production accuracy (Edwards et al, 2004;Velleman and Vihman, 2007;Vihman and Keren-Portnoy, 2013).…”

“…Based on our own in-depth examinations of coarticulatory mechanism in both adults (Abakarova et al, 2018) and children (Noiray et al, 2018;Rubertus and Noiray, 2018), we have argued that (young) speakers exhibit gradients of coarticulation degree within a continuum from a more syllabic to a more segmental organization. The degree to which segment overlap depends on the gestural demands associated with the combined segments.…”

“…For each target tongue contour, a 100-point spline was automatically generated, and the x-and y-coordinates for each point were extracted. In subsequent analyses, we used the horizontal x-coordinate for the highest y-coordinate point of the tongue dorsum to reflect its variation in the anterior-posterior dimension (e.g., anterior position for /i/, posterior position for /u/, e.g., Abakarova et al, 2018). Data were normalized for each participant by setting the most anterior tongue dorsum position during the target vowel midpoints to 0 and the most posterior tongue dorsum position to 1.…”

Recording and analyzing kinematic data in children and adults with SOLLAR: Sonographic & Optical Linguo-Labial Articulation Recording system

“…It allows for the simultaneous recording of the audio speech signal via a microphone, tongue movement via UTI, and lip movement via video recording. The platform has been validated in several studies with children starting from three years of age (Noiray et al, 2018, Noiray et al, 2019a, Noiray et al, 2019b as well as with adults (Abakarova, Iskarous, & Noiray, 2018). In the remainder of this article, we make suggestions for designing a child-friendly recording environment and describe the data collection protocol developed within the SOLLAR platform (Section 2).…”