The Perceptual Distinctiveness of the [n-l] Contrasts in Different Vowel and Tonal Contexts

Abstract

The alveolar nasal [n] and its homorganic lateral [l] widely exit in the world language systems. Presence/absence of the phonological contrasts between syllable-initial [n-l] differs across Chinese dialects. Typology across Chinese dialects observed that the [n-l] contrasts occurred (i) more frequently in the [_a] context than in the [_i] context, and (ii) more frequently when the tone of the syllable starts with a H(igh) (e.g., HH, HL) than when it starts with a L(ow) (e.g., LH, LL). Two research questions were raised based on these two typological patterns: (i) Does vowel context influence the perceptual distinctiveness of the [n-l] contrasts, specifically, is [na-la] more distinct than [ni-li]? (ii) Does tonal context influence the perceptual distinctiveness of the [n-l] contrasts, specifically, is [n-l] more distinct when appearing with a H(igh) tone than with a L(ow) tone? These research questions were addressed in two speeded AX discrimination experiments to measure the psychoacoustic distinction of sound pairs.

In Experiment 1, thirty-six native Mandarin listeners were tested with the audio stimuli [na-la] and [ni-li] pairs. Assuming that a shorter response time and a higher discrimination accuracy to suggest a larger perceptual distinctiveness, the results indicated that a [n-l] contrast is perceptually more distinct in the [_a] context than in the [_i] context. This is consistent with the observations in previous typological surveys across Chinese dialects, i.e., [na-la] is more frequent than [ni-li].

In Experiment 2, the same group of listeners discriminated [na-la] and [ni-li] pairs when the syllables bear different tones (HH, HL, LH, LL). The results indicated that a [n-l] contrast is perceptually more distinct when the tone of the syllable begins with H (i.e., HH and HL) than when it begins with L (i.e., LH and LL). Results from this experiment were in accord with the typological pattern that [n-l] contrasts are more frequently when the tone starts with H than L.

In general, the results in this study showed that the psychoacoustic distinction of a [n-l] contrast is influenced by vowel and tonal context. Furthermore, this study supported the connection between the perceptual distinctiveness of a sound pair and the cross-linguistic typology of phonological contrasts as observed in literature.

Date of Award	9 Jan 2024
Original language	English
Supervisor	Mingxing LI (Supervisor)