Tongue Curves Research Articles

Tongue movements in the production of /l/ in children with and without speech sound disorders in different ages.

this study used the ultrasonography of the tongue movements and the dynamic models of speech production to characterize the articulatory gestures of in the production of /l/ at the Brazilian Portuguese in different age groups, comparing them between typical and atypical children. the sample consisted of 30 typical and 30 atypical children between ages of four and eight-years-old, who underwent speech-language and ultrasonographic evaluations. The evaluation was realized by recording words reproduction with the sound /l/ and the following vocalic contexts: /a/, /i/ and /u/, repeating six times for each word. The software for recording and analysis was Articulate Assistant Advanced (AAA). The quantitative analysis considered the 42 points that intercepted the tongue curves in each image to describe the articulatory gestures; the estimation of the mean lines of each curve and the confidence intervals between typical and atypical children groups; and the differences between the mean tongue contours curves according to age group. the results presented a tongue tip elevation and dorsal and root retraction in /l/. Typical children, regardless of age, showed a greater refinement of articulatory tongue gestures than the atypical ones. In older children, there was more delimitation in the mean tongue contours from the tongue tip to the root. the ultrasonography of the tongue movements is a substantial implement to characterize the articulatory gestures of /l/, to the differentiation between typical and atypical productions in this sound, and observation of the development of the articulatory gestures.

Differentiating tongue shapes for alveolar-postalveolar and alveolar-velar contrasts

This paper is focussed on differentiating midsagittal tongue shapes for alveolar-postalveolar and alveolar-velar contrasts in place of articulation. In addition to two established measures assessing the shape of a tongue curve, three new indices are introduced, which capture more fine grained distinctions in tongue shape, through quantifying the extent of curvature at different locations along the tongue contour. In order to establish whether the indices can be applied across a range of ultrasound recording settings, including those where the transducer is hand-held rather than stabilised in relation to the head, the length of the tongue curve was systematically manipulated, since differences in the length of the imaged tongue contour are likely to occur in non-head-stabilised recordings. The study identified the measures that differentiated between contrasting places of articulation, producing robust results regardless of differences in the length of the imaged tongue curve. Combinations of measures were found to capture place of articulation distinctions more accurately than individual measures. The paper includes a discussion of how such combinations of measures can be used for studying the development of phonological contrasts in typical child speech, as well as the realisation of alveolar-postalveolar and alveolar-velar oppositions in disordered speech.

Voiceless alveolar stop coarticulation in typically developing 5-year-olds and 13-year-olds

ABSTRACTIn this study, vowel-on-consonant lingual coarticulation at [t] closure offset was compared in 5-year-old children and 13-year-old adolescents. The study aimed to establish whether, by the end of the closure, children from the younger age group adjust the tongue shape to the following vowels to the same extent as adolescents. Ten 5-year-olds and ten 13-year-olds, all speakers of Scottish Standard English, produced [t]-vowel syllables with the vowels [i] and [a], in a carrier phrase. Measures of tongue shape based on midsagittal ultrasound imaging data were used to compare anticipatory coarticulation and within-speaker variability across groups. Both age groups changed the extent of tongue dorsum bunching in order to coarticulate the consonant with the following vowels. The 5-year-old children, unlike the adolescents, did not consistently modify the bunching location within the tongue curve to accommodate the tongue shape to that of the upcoming vowel. Token-to-token variability was significantly greater in the younger age group. The results suggest that vowel-on-[t] coarticulatory patterns produced by typically developing children are affected by the development of motor control, with articulatory constraints on the tongue limiting the extent of lingual coarticulation in 5-year-old children. The findings on typical coarticulation development are relevant for clinical practice, and they highlight the need for more detailed descriptions of how phonetic characteristics of speech sounds affect coarticulation throughout childhood.

O contraste entre oclusivas alveolares e velares em dados típicos de fala: análises acústica e ultrassonográfica

This study used acoustic and articulatory analyses to characterize the contrast between alveolar and velar stops with typical speech data, comparing the parameters (acoustic and articulatory) of adults and children with typical speech development. The sample consisted of 20 adults and 15 children with typical speech development. The analyzed corpus was organized through five repetitions of each target-word (/'kap ə/, /'tapə/, /'galo/ e /'daɾə/). These words were inserted into a carrier phrase and the participant was asked to name them spontaneously. Simultaneous audio and video data were recorded (tongue ultrasound images). The data was submitted to acoustic analyses (voice onset time; spectral peak and burst spectral moments; vowel/consonant transition and relative duration measures) and articulatory analyses (proportion of significant axes of the anterior and posterior tongue regions and description of tongue curves). Acoustic and articulatory parameters were effective to indicate the contrast between alveolar and velar stops, mainly in the adult group. Both speech analyses showed statistically significant differences between the two groups. The acoustic and articulatory parameters provided signals to characterize the phonic contrast of speech. One of the main findings in the comparison between adult and child speech was evidence of articulatory refinement/maturation even after the period of segment acquisition.

Imagens de ultrasonografia de língua pré e pós terapia de fala

RESUMO O objetivo deste estudo foi analisar a imagem de ultrassonografia do movimento de língua durante a produção de oclusivas alveolares e velares, pré e pós-terapia de fala. Um menino com cinco anos de idade e diagnóstico de desvio fonológico, apresentando o processo de anteriorização de oclusivas velares, participou da presente pesquisa. Foram coletados os dados articulatórios (imagem de ultrassom do movimento de língua) e perceptivo auditivo dos fones [t], [d], [k] e [g], antes e após 25 sessões de terapia. Quanto aos resultados obtidos no momento pré-terapia, aparentemente, foi detectada uma indiferenciação gestual ao serem observadas as três repetições da curva de língua das oclusivas velares, sugerindo a presença de uma dependência entre os articuladores de ponta e corpo de língua. No momento pós-terapia, uma mudança na configuração do gesto de língua de [k] e [g] foi verificada. As curvas passaram a apresentar uma posteriorização do movimento de língua, sincronicamente com uma elevação do seu corpo, concordando com o padrão adulto. Dessa forma, os achados de ultrassonografia foram capazes de evidenciar uma possível superação da estratégia de anteriorização de oclusivas velares, detectada em análise perceptiva auditiva inicial. Além disso, estes resultados pareceram reforçar a ideia de contrastes encobertos na fala de crianças com desvio fonológico.

Quantifying lingual coarticulation using ultrasound imaging data collected with and without head stabilisation

Previous studies reporting the use of ultrasound tongue imaging with clinical populations have generally provided qualitative information on tongue movement. Meaningful quantitative measures for use in the clinic typically require the speaker’s head to be stabilised in relation to a transducer, which may be uncomfortable, and unsuitable for young children. The objective of this study was to explore the applicability of quantitative measurements of stabilisation-free tongue movement data, by comparing ultrasound data collected from 10 adolescents, with and without head stabilisation. Several measures of tongue shape were used to quantify coarticulatory influence from two contrasting vowels on four different consonants. Only one of the measures was completely unaffected by the stabilisation condition for all the consonants. The study also reported cross-consonant differences in vowel-related coarticulatory effects. The implications of the findings for the theory of coarticulation and for potential applications of stabilisation-free tongue curve measurements in clinical studies are discussed.

Examining suprasegmental and morphological effects on constriction degree with ultrasound imaging

Two case studies of ultrasound imaging use tongue shape differences to investigate whether suprasegmental influences affect the articulatory implementation of otherwise equivalent phonemic sequences. First, we examine whether word-medial and word-final stop codas have the same degree of constriction (e.g., "blacktop" vs. "black top"). Previous research on syllable position effects on articulatory implementation have conflated syllable position with word position, and this study investigates whether each prosodic factor has an independent contribution. Results indicate that where consistent differences are found, they are due not to the prosodic position but to speaker-specific implementation. Second, we examine whether morphological status influences the darkness of American English /l/ in comparing words like "tallest" and "flawless." While the intervocalic /l/s in "tall-est" and "flaw-less" are putatively assigned the same syllabic status, the /l/ in "tallest" corresponds to the coda /l/ of the stem "tall" whereas that of "flawless" is the onset of the affix "-less." Results indicate that /l/ is darker—the tongue is lower and more retracted—when corresponding to the coda of the stem word. Data in both studies were analyzed with smoothing spline ANOVA, an effective statistical technique for examining differences between whole tongue curves.

Using Ultrasound to Quantify Tongue Shape and Movement Characteristics

Objective : Previous experimental studies have demonstrated abnormal lingual articulatory patterns characterizing cleft palate speech. Most articulatory information to date has been collected using electropalatography, which records the location and size of tongue-palate contact but not the tongue shape. The latter type of data can be provided by ultrasound. The present paper aims to describe ultrasound tongue imaging as a potential tool for quantitative analysis of tongue function in speakers with cleft palate. A description of the ultrasound technique as applied to analyzing tongue movements is given, followed by the requirements for quantitative analysis. Several measures are described, and example calculations are provided. Measures : Two measures aim to quantify overuse of tongue dorsum in cleft palate articulations. Crucially for potential clinical applications, these measures do not require head-to-transducer stabilization because both are based on a single tongue curve. The other three measures compare sets of tongue curves, with the aim to quantify the dynamics of tongue displacement, token-to-token variability in tongue position, and the extent of separation between tongue curves for different speech sounds. Conclusions : All measures can be used to compare tongue function in speakers with cleft palate before and after therapy, as well as to assess their performance against that in typical speakers and to help in selecting more effective treatments.

Coarticulation as an Indicator of Speech Motor Control Development in Children: An Ultrasound Study

There are still crucial gaps in our knowledge about developmental paths taken by children to adult-like speech motor control. Mature control of articulators during speaking is manifested in the appropriate extent of coarticulation (the articulatory overlap of speech sounds). This study compared lingual coarticulatory properties of child and adult speech, using ultrasound tongue imaging. The participants were speakers of Standard Scottish English, ten adults and ten children aged 6-9 years. Consonant-vowel syllables were presented in a carrier phrase. Distances between tongue curves were used to quantify coarticulation. In both adults and children, vowel pairs /a/-/i/ and /a/-/u/ significantly affected the consonant, and the vowel pair /i/-/u/ did not. Extent of coarticulation was significantly greater in the children than in the adults, providing support for the notion that children's speech production operates with larger units than adults'. More within-speaker variability was found in the children than in the adults.

Comparing tongue shapes from ultrasound imaging using smoothing spline analysis of variance

Ultrasound imaging of the tongue is increasingly common in speech production research. However, there has been little standardization regarding the quantification and statistical analysis of ultrasound data. In linguistic studies, researchers may want to determine whether the tongue shape for an articulation under two different conditions (e.g., consonants in word-final versus word-medial position) is the same or different. This paper demonstrates how the smoothing spline ANOVA (SS ANOVA) can be applied to the comparison of tongue curves [Gu, Smoothing Spline ANOVA Models (Springer, New York, 2002)]. The SS ANOVA is a technique for determining whether or not there are significant differences between the smoothing splines that are the best fits for two data sets being compared. If the interaction term of the SS ANOVA model is statistically significant, then the groups have different shapes. Since the interaction may be significant even if only a small section of the curves are different (i.e., the tongue root is the same, but the tip of one group is raised), Bayesian confidence intervals are used to determine which sections of the curves are statistically different. SS ANOVAs are illustrated with some data comparing obstruents produced in word-final and word-medial coda position.

Smoothing spline analysis of variance (ANOVA) for tongue curve comparison

Ultrasound imaging of the tongue is an increasingly common technique in speech production research. One persistent issue regarding ultrasound data is how to quantify them. Researchers often want to determine whether the tongue shape for an articulation under two different conditions (e.g., consonants in phrase-initial versus phrase-medial position) is the same or different. To address this issue, a method for comparing tongue curves using a smoothing spline ANOVA has been developed (SSANOVA) [Gu, 2002, Smoothing spline ANOVA models]. The SSANOVA is a technique for comparing curve shapes (splines) for two sets of data to determine whether there are significant differences between the curve types. Data sets contain 8–10 repetitions of each of the relevant tongue curves being compared. If the interaction term of the SSANOVA model is statistically significant, then the groups have different shapes. Since the interaction may be significant even if only a small section of the curves is different (i.e., the tongue root is the same, but the tip of one group is raised), Bayesian confidence intervals are used to determine which sections of the curves are statistically different. SSANOVAs are illustrated with some data comparing obstruents produced in word-final and word-medial coda position.

Principal Components Representation of the Two-Dimensional Coronal Tongue Surface

This paper uses principal components (PC) analysis to represent coronal tongue contours for the 11 vowels of English in two consonant contexts (/s/, /l/), based upon five replicated measurements in three sessions for each of 6 subjects. Curves from multiple sessions and speakers were overlaid before analysis onto a common (x, y) coordinate system by extensive preprocessing of the curves including: extension (padding) or truncation within session, translation, and truncation to a common x range. Four PCs plus a mean level allow accurate representation of coronal tongue curves, but PC shapes depend strongly on the degree of padding or truncation. The PCs successfully reduced the dimensionality of the curves and reflected vowel height, consonant context, and physiological features.

Characterization of tongue shape during normal speech

Averaged tongue shapes and polynomial equations were computed for five phonemes in order to determine aspects of tongue curve which distinguish between phonemes. Five repetitions of each of the phonemes /i/, /u/, /o/, /ae/, and /ɑ/ were produced by a normal volunteer using the carrier phrase “I can say /dVd/ again.” An ultrasound sector scanner was used to obtain midsagittal pictures of the posterior section of the tongue from vertical to 85° back into the throat. The pictures were digitized, and the resulting points were used to generate average tongue shapes and average quadratic and cubic fits for each phoneme. While both techniques provide information which allows the researcher to distinguish between the five phonemes used, only the averaged tongue shapes adequately reflect certain details of tongue shape.