The production of articulatorily complex consonants in Estonian by children and adults

Our ongoing research programme aims to understand how children acquire the motor control skills needed for speech. In this pilot study, we looked at how Estonian children and adults produce consonants that require complex tongue gestures. Ultrasound and acoustic data were collected from 8 adults and 8 children aged 4-5 and 6-8. The participants produced palatalised and non-palatalised consonants. Analysis of tongue shapes using Number of Inflections and Modified Curvature Index and showed that palatalised productions consistently resulted in more complex and differentiated tongue configurations (more inflections, higher curvature). Children produced a smaller difference in tongue shape between palatalised and non-palatalised consonants, indicating ongoing maturation of articulatory control, vocal tract, and tongue shape.