Boundary-conditioned anticipatory tonal coarticulation in Standard Mandarin

The goal of this study is to examine (1) whether and how the F0 contour of a sequence of neutral tones in Standard Mandarin is affected by the following full tone due to anticipatory tonal coarticulation, (2) whether and how the degree of anticipatory tonal coarticulation varies as a function of the strength of an intervening boundary, and (3) whether boundary-conditioned anticipatory tonal coarticulatory variations can be accounted for by boundary-induced durational changes. By using generalized additive mixed models to analyze time-varying F0 contours of neutral-tone sequence, we are able to formally detect anticipatory tonal coarticulation effects across different boundary conditions while simultaneously taking into account individual variations of 20 speakers. Results show that (a) F0 contours of neutral-tone sequence can be affected by both assimilatory and dissimilatory anticipatory effects and anticipation could spread to non-adjacent neutral tones, that (b) anticipatory tonal coarticulation becomes weaker when crossing a strong boundary than when crossing a weak boundary, and that (c) boundary-induced anticipatory tonal coarticulation reduction cannot be simply accounted for by boundary-induced lengthening effect. Based on the results, we argue that the anticipatory tonal coarticulation patterns reported in this study are more consistent with the soft template mark-up language (Stem-ML) model than with the parallel encoding and target approximation (PENTA) model, and that boundary-induced anticipatory tonal coarticulation reduction is primarily the result of active speech planning.