Tone and Intonation Processing: From Ambiguous Acoustic Signal to Linguistic Representation
The most prominent prosodic feature of tonal languages such as Standard Chinese is their use of pitch to distinguish lexical meanings (i.e., tone). However, speech ambiguity arises in Standard Chinese because the same pitch contour can also cue another linguistic function (i.e., intonation) in the same linguistic system. As most Standard Chinese speakers also speak another local Chinese dialect, speed ambiguity can furthermore arise when the same or similar pitch contours cue the same linguistic function (e.g., tone), but different categories of that function in two linguistic systems of a bi-dialectal speaker. This dissertation investigates how pitch is processed within a linguistic system (i.e., Standard Chinese) and across two linguistic systems (i.e., Standard Chinese and Xi’an Mandarin) when the same pitch contour cues different linguistic functions (i.e., tone and intonation) or different categories of the same linguistic function (i.e., tone).
Through four experimental studies, this dissertation has demonstrated that pitch processing in Standard Chinese is subject to both within- and cross-linguistic influences. The ambiguous acoustic signals due to dual functions of the F0 channel in signalling tone and intonation in Standard Chinese cause pitch processing difficulty at the sentential level. This pitch processing difficulty has a neural correlate and can be resolved via top-down information provided by a constraining semantic context. A closely related Chinese dialect that shares tonal similarities with Standard Chinese can also cause acoustic ambiguities. The cross-dialect tonal similarities affect tone processing and further interfere in lexical access during spoken word recognition in bi-dialectal tonal language speakers.