Phonetic contrasts in Cantonese tone acquisition (Mok et al., 2020)

Purpose: Previous studies showed both early and late acquisition of Cantonese tones based on transcription data using different criteria, but very little acoustic data were reported. Our study examined Cantonese tone acquisition using both transcription and acoustic data, illustrating the early and protracted aspects of Cantonese tone acquisition.
Method: One hundred fifty-nine Cantonese-speaking children aged between 2;1 and 6;0 (years;months) and 10 reference speakers participated in a tone production experiment based on picture naming. Natural production materials with 30 monosyllabic words were transcribed by two native judges. Acoustic measurements included overall tonal dispersion and specific contrasts between similar
tone pairs: ratios of average fundamental frequency height for the level tones (T1, T3, T6), magnitude of rise and inflection point for the rising tones (T2, T5), magnitude of fall, H1*–H2*, and harmonic-to-noise ratio for the low tones (T4, T6). Auditory assessment of creakiness for T4 was also included.
Results: Children in the eldest group (aged 5;7–6;0) were still not completely adultlike in production accuracy, although two thirds of them had production accuracy over 90%. Children in all age groups had production accuracy significantly higher than chance level, and they could produce the major acoustic contrasts between specific tone pairs similarly as reference speakers. Fine phonetic detail of the inflection point and creakiness was more challenging for children.
Conclusion: Our findings illustrated the multifaceted aspects (both early and late) of Cantonese tone acquisition and called for a wider perspective on how to define successful phonological acquisition.

Supplemental Material S1. Accuracy of top-, mid-, and bottom-ranking children of each age group, and one-sample t-test results.

Supplemental Material S2. Pairwise comparisons using Tukey (HSD) tests for tonal dispersion (middle column) and phonological pitch range (right column).

Supplemental Material S3. Results of two-tailed paired-sample t-tests comparing T2 vs. T5 for the magnitude of rise (left columns) and post hoc pairwise comparisons with Tukey correction for the position of the inflection point (right columns).

Supplemental Material S4. Results of two-tailed paired-sample t-tests comparing the magnitude of fall for T4 vs T6.

Supplemental Material S5. Results of Tukey’s HSD post hoc tests comparing the HNR between age groups.

Supplemental Material S6. Post hoc pairwise comparisons using Fisher’s Exact Test of Independence comparing creaky tokens among age groups.

Mok, P. P. K., Li, V. G., & Fun, H. S. H. (2020). Development of phonetic contrasts in Cantonese tone acquisition. Journal of Speech, Language, and Hearing Research. Advance online publication. https://doi.org/10.1044/2019_JSLHR-19-00152