Spatial and temporal lingual coarticulation and motor control in preadolescents

Area of Science:

• Speech Science
• Linguistics
• Motor Control

Background:

• Understanding speech development requires examining articulatory precision and coarticulation in children.
• Preadolescents may exhibit different lingual kinematics and coarticulation patterns compared to adults.

Purpose of the Study:

• To compare coarticulation and lingual kinematics between preadolescents and adults.
• To determine if preadolescents have greater random variability in tongue posture.
• To investigate age-related differences in lingual coarticulation patterns.

Main Methods:

• Recorded high-speed ultrasound tongue data synchronized with acoustic signals from 15 preadolescents (10-12 years) and 15 adults.
• Analyzed tongue shape contours at 9 normalized time points during fricative-vowel sequences (/s/, /ʃ/).
• Examined coarticulation during schwa-fricative-/a/ and schwa-fricative-/i/ sequences.

Main Results:

• No significant age-related differences in random tongue posture variability were found.
• The degree of coarticulation was similar between groups when a vowel effect was significant.
• The onset of coarticulation for /ʃ/ was significantly later in preadolescents compared to adults and their own /s/.

Conclusions:

• Preadolescents demonstrate adult-like precision in tongue control and spatial aspects of anticipatory coarticulation.
• Some immaturity persists in the motor programming of complex tongue movements in preadolescents.
• Findings suggest a nuanced developmental trajectory for speech articulation.