Development of Extrinsic Normalization of Lexical Tones in Cantonese-Speaking Children

This study aimed to investigate the age by which Cantonese-speaking children reach adult level in using contextual cues to adjust for speech variability in identifying level tones. Another aim of this study was to explore the external and internal factors on the level tone normalization, that is, the influence of context type and individual attributes including linguistic skill and musical pitch sensitivity.

The study involved 62 Cantonese-speaking children aged 7-10 years (31 boys, 31 girls) and 24 young adults (12 men, 12 women). Participants were asked to identify Cantonese level tones in different conditions: condition without context and condition with contexts: speech, music, or pure tone. Child participants' linguistic skill was assessed using a subtest of the standardized language test, and their sensitivity to musical pitch changes was assessed using three subtests related to pitch perception of Montreal Battery of Evaluation of Musical Abilities.

Children aged 8 years and above showed comparable performance with adults in the condition with speech context, and performed significantly better than younger children. Nonspeech contexts (music and pure tone) did not elicit contrastive context effect in participants across all age groups. The children with better linguistic skill or higher musical pitch sensitivity performed better in using speech contextual cues to identify level tones.

Cantonese-speaking children matured in their ability to normalize level tones at age of 8 years. This ability was positively associated with linguistic skill and musical pitch sensitivity. In addition, Cantonese level tone normalization is a speech-specific perceptual process.