Acquisition of articulatory control for sentential focus in children

The present study examined articulator movement changes associated with the production of sentential focus in 4, 7 and 11-year-old children and adults. A facial capture system was used to track jaw, lower lip and upper lip movements while words were produced with and without focus in phrase-final and non-final positions. Adults produced focused words with significantly greater movement duration, displacement and velocity than unfocused words. Significant differences in duration, displacement and velocity between focused and unfocused productions were seen in the 7 and 11 year olds, although these results were not as consistent as those seen in the adults. Articulator movement differences between focused and unfocused words were seen in both the phrase-final and non-final positions in adults yet only in the phrase-final position in children. Findings suggest that children begin to modify articulator movement to mark sentential focus between 7 and 11 years of age and are likely to continue to refine movement patterns for this prosodic task throughout adolescence.