Impoverished acoustic input triggers probability-based tone processing in mono-dialectal Mandarin listeners

Previous research on Mandarin spoken word recognition suggests that when processing lexical tone native listeners tune to various acoustic properties of the incoming signal such as f0 height, contour and change. These studies overlook the uneven distribution of tone across the Mandarin lexicon; given a particular string of segments, native listeners may be more likely to anticipate a certain tone due to prior experience with the language. The present study used the gating paradigm to investigate how much of the acoustic signal is needed for listeners to trigger such probability-based tone processing. Duration-blocked gates were generated from twelve low frequency and twelve high frequency mono-syllabic morphemes, with each syllable carrying either the most or least probable tone based on spoken corpora. Results from 22 mono-dialectal Mandarin speakers indicate that listeners immediately begin making use of tonal probability information after hearing only the onset and 40 ms of the vowel, primarily when hearing infrequent syllables. These findings demonstrate that the processing of suprasegmental information can be initiated with previously learned distributional knowledge until sufficient acoustic cues inform the listener of an incoming word.