This study investigates the effect of language attrition and tone sandhi on speech processing of Taiwanese tones. The mid level tone was previously found to be the most confusing category, and is largely confused with low-falling tone. This study argues that the tonal errors are caused by the effect of language attrition and tone sandhi. Three perception and one production tasks were conducted on 15 fluent speakers and 30 attriters. The results show that attriters significantly make more errors than fluent speakers. In the production task, both groups tend to mispronounce mid level tone as low-falling tone, but in the perception tasks, they tend to misperceive the mid level tone as high level tone. The strong tendency is argued to be determined by the effect of tone sandhi and phonetic similarity. The findings support the effect of language attrition, and suggest that both phonetic and phonological factors exert an influence on Taiwanese tonal processing.

Index Terms: language attrition, mid level tone, perception-production asymmetry, phonetic similarity, tone sandhi