Some phonological, syntactic, and cognitive factors behind phrase-final lengthening in spontaneous Japanese: A corpus-based study

Abstract In this study, we investigated segment lengthening in spontaneous Japanese based on a quantitative analysis of a large-scale corpus, focusing on the following three locations at which lengthening frequently occurs: the final segments of (i) clause-initial preface tokens (fillers and conjunctions), (ii) clause-initial wa-marked topic phrases, and (iii) clause-final particles. Two cognitive factors, namely clause complexity and boundary depth, were precisely analyzed using statistical models that also accounted for several phonological and syntactic factors. The results showed that in addition to the reliably strong effects of some phonological factors such as the presence of a following pause and the presence of boundary pitch movement, the effects of two cognitive factors were also evident. The way in which lengthening is related to the cognitive factors, however, varies significantly by location and token type. Lengthening of clause-final particles was affected by boundary depth, while lengthening of the topic marker wa of clause-initial topic phrases was influenced by clause complexity. Lengthening of the filler e was affected by both factors. A significant interaction between the two factors was also observed for the filler ano. We discuss the implications of these results as well as agendas for improving the current analysis.