Children's Processing of Tonal Alternations: A View from Two Tone Sandhi Rules in Mandarin

Mandarin Chinese has two different types of tone sandhi (TS) rules. One is known as the Tone 3 Sandhi (T3S) rule, a general rule that applies to the T3 syllable, whereby a T3-T3 sequence is realized as T2-T3. The other is associated with specific words and is often referred to as morpheme-specific TS rules, whereby the underlying T4 surfaces as T2 when followed by another T4. The extant literature has yielded mixed results on children's acquisition of the general T3S rule, and less is known about their acquisition of morpheme-specific TS rules. To fill the gap, the present study explored 4- to 6-year-old Mandarin-speaking children's understanding of the general T3S rule associated with hen (meaning 'very') and the morpheme-specific TS rule associated with bu (meaning 'not'), using a tone sandhi predictive processing task. The results showed that the children exhibited a developmental trajectory in their comprehension of the two TS rules, with the 6-year-olds performing significantly better than the 4- and 5-year-olds. To explore how core cognitive abilities like Working Memory (WM, measured by the n-back task) contributed to the observed developmental trajectory, we also examined how the children's WM capacity was associated with their performance in the tone sandhi predictive processing task. The findings showed that the children's scores in the 1-back task reliably predicted their performance in the processing of the morpheme-specific TS rule, highlighting the interaction between the children's knowledge of TS rules and their WM capacity during their development.