Development of Lexical Tone Production in Disyllabic Words by 2- to 6-year-old Mandarin-speaking Children

This study investigated children\u27s development in the production of Mandarin lexical tones in familiar disyllabic words and tested the hypothesis that disyllabic tone contours with more complex fundamental frequency contours are more difficult for children to produce. Participants were forty-four 2- to 6-year-old monolingual Mandarin-speaking children and 12 mothers. Their disyllabic tone productions were elicited by picture naming and low-pass filtered to eliminate lexical information while retaining the fundamental frequency contours. Three Mandarin-speaking judges listened to the filtered stimuli, and categorized the children\u27s and adult\u27s disyllabic tones. Acoustic analysis was performed on selected accurate child and adult productions and on a sample of children\u27s inaccurate productions. Judges identified adults\u27 productions as the intended tones with very high accuracy. As a group, children\u27s productions were judged significantly less correctly than adults\u27. Judged correctness increased significantly with age, but even 5- to 6-year-old children\u27s disyllabic tones were judged as less accurate overall than adults\u27. Large inter-subject variability was observed in 2- to 4-year-old children\u27s performance. Some disyllabic tones, particularly non-compatible tone combinations (i.e., tones with large transitions at the boundary between the syllables), remained difficult even for older children. When children made errors, they usually produced one of the tones correctly; error patterns suggested that they modified the first tone to be more compatible with the second tone (i.e., showed anticipatory coarticulation patterns), unlike the adult patterns which show more carry-over coarticulatory effects. When the four lexical tones were analyzed separately, significant context effects were found. Children produced the high level tone (T1) more accurately in the second than the first syllable. The rising tone (T2) was more accurately produced in compatible than non-compatible contexts. The low, dipping tone (T3) and falling tone (T4) were produced least accurately in the first syllable when the tone combination was non-compatible. In conclusion, acquisition of disyllabic Mandarin tone contour appears to be a gradual process that spans more than six years to achieve mastery. Children have more difficulty producing complex tone contours that demand rapid f0 changes, suggesting the influence of immature physiological control of laryngeal gestures on the production of lexical tone contours in continuous speech