Mechanisms of tone sandhi rule application by tonal and non-tonal non-native speakers

This study is the first comprehensive acoustic study to examine the acquisition of two Mandarin tone sandhi rules: the third tone sandhi and the more phonetically motivated, half-third sandhi rule by both tonal (Cantonese) and non-tonal (American English) speakers using a Wug Test. Participants were asked to form disyllables from two monosyllabic morphemes. To test for the operation of the lexical versus the computation mechanisms in sandhi rule application, both real and various types of wug (nonsense) morphemes were included. Functional data analysis revealed that Cantonese and American speakers apply the two rules similarly on both real words and wug words, suggesting that the sandhi forms are stored as part of the representation of the abstract Tone 3 (T3) category, and computation of allophonic variants is likely to be involved during production. However, in their computation of tone sandhi rules, L2 learners showed less detailed and less accurate production of tonal contours compared to native speakers, due, perhaps, to less detailed phonological representations of allophonic variants. In general, Cantonese speakers performed better than American speakers. Perceptual mapping between Mandarin sandhi T3 to existing Cantonese tone categories may be responsible for the observed pitch contours among Cantonese speakers. Finally, no phonetic bias was found in the application of the two sandhi rules among these groups of L2 learners, which is likely due to more variability in L2's speech, obscuring any differences that may exist.