Identification of synthesized Mandarin tones by Northern Vietnamese speakers

Tones in Northern Vietnamese are distinguished by pitch variations and phonation types, but falling pitch slopes are not considered as a major cue that its speakers rely on in tonal contrast. This may contribute to difficulties that native speakers of Northern Vietnamese are faced with when learning Mandarin tones, especially the distinction between the level (T1) and the falling (T4) tones. To examine how Northern Vietnamese speakers perceive the distinction between T1 and T4 in Mandarin and how well they adapt phonetic cues underlying the non-native distinction, an ABX identification experiment is carried out on perception of synthesized pitches with two inter-stimuli-intervals (ISI) at 500ms and 1500ms. Results suggest a combined effect of pitch slopes and pitch heights, the former of which claims more robust influence on tone perception. However, a reversed pattern is found when the ISI equals 500ms, where pitch heights exert a stronger effect on tone identification than pitch slopes.