Neural mechanisms for phonological alternation with high and low productivity - a case study on Chinese tone sandhi

NSF grant – Jie Zhang, KU Linguistics

Phonological alternation, whereby a morpheme takes on different phonological forms in different contexts, is a fundamental concern for phonology. Behavioral studies on tonal alternation, also known as "tone sandhi," have shown that alternation patterns extend to novel words in different ways, i.e., have different productivity, depending on the phonological nature of the pattern. This suggests that different mechanisms may be involved in the processing of phonological alternation. In this two-year project, event-related potentials (ERPs) will be used to examine the time-course of the encoding of phonological alternation in speech production from the perspective of tone sandhi. It is hypothesized that productive sandhi patterns are primarily subserved by a computation mechanism, which computes the sandhi form according to phonological context, while unproductive tone sandhis are primarily subserved by a lexical mechanism, which retrieves the stored sandhi form of existing words from memory. Based on earlier neurolinguistic findings and pilot results, it is further hypothesized that the encoding of unproductive sandhis engages neural activities in an earlier time-window of lexical retrieval 150~225ms after initiation of production and is sensitive to lexical frequency differences; the encoding of productive sandhis, on the other hand, engages neural activities in a later time-window of phonological encoding (400~600ms) and is less sensitive to lexical frequency differences. To test these hypotheses, the ERPs during tone sandhi production in Mandarin and Taiwanese Southern Min will be examined in five experiments.