《2021年度最佳碩士論文獎》

中文：台灣華語韻尾鼻輔音聲學感知之權重
英文：Cue-weighting in the perception of Taiwan Mandarin nasal codas
得主：林奎宏 (國立陽明交通大學外文所)

指導教授：盧郁安教授

中文摘要：

本論文探討台灣華語語者如何感知合流中的韻尾齒齦/n/與軟齶/ŋ/鼻輔音，尤其在非開元音(/ə/N與/i/N)的合流環境下，與在開元音後(/a/N)無流失對比的環境下。文獻顯示在/i/N環境下/n/通常合流至[ŋ]，但在南台灣有另類的/ŋ/合流至[n]的方向；在/ə/N環境下南北台灣華語語者卻皆將/ŋ/合流至[n] (Fon et al., 2011)。雖在構音位置上的對比正逐漸消失中，但在韻核鼻音化程度與鼻韻尾音長上的對比依然存在(Chiu et al., 2020; Chuang, 2017)。

實驗一檢測受試者在感知韻尾鼻輔音時對共振峰轉變的依賴程度。結果顯示：（一）受試者的正確率在/a/N環境下達到天花板效應(M= 97.2%)，反應時間亦是最快的(M= 1038.9毫秒)；（二）[in]的正確率比[iŋ]高，而[əŋ]的正確率比[ən]高，反應時間皆較/a/N環境長；（三）某些南部受試者的[in]正確率卻較[iŋ]低。

實驗二透過合成韻核/韻尾鼻音音長，來檢驗鼻韻尾音長與鼻音發音位置感知的關聯性。實驗結果顯示在合流的環境下([ən]與[iŋ])受試者在鼻韻尾感知確實會受到不同韻核/韻尾鼻音音長的影響；然而在非合流環境中([əŋ]與[in])，台灣華語語者主要還是依賴元音共振鋒的轉變來區辨韻尾鼻輔音。

English Abstract

This thesis investigates how Taiwan Mandarin speakers perceive nasal codas. TM nasal codas, /n/ and /ŋ/ are reported to be undergoing merging in non-low vowel contexts (/ə/N and /i/N), as opposed to the low vowel context (i.e., /a/N). Specifically, in the /i/N context, /n/ is generally merged into [ŋ]; yet, there is a sub-pattern merging into [n] in Southern Taiwan. In the /ə/N context, however, northern and southern TM speakers overall merge /ŋ/ into [n] (Fon et al., 2011). While the contrast in the place of articulation fades away, previous studies have shown that TM speakers maintain the contrast by the degree of nasalization of the pre-nasal vowels and by the nasal coda duration (Chiu et al., 2020; Chuang, 2017).

TM participants’ reliance on formant transitions in perception was tested in Experiment 1. Results showed that (i) participants reached a ceiling effect (M= 97.2%) in accuracy with the shortest response time (M= 1038.9 ms) in the /a/N context, that (ii) a higher accuracy for [in] compared to [iŋ] and a higher accuracy for [əŋ] compared to [ən] were observed, and that (iii) a lower accuracy for [in] compared to [iŋ] for some participants from Southern Taiwan.

Experiment 2 was conducted to examine the relevance of nasal coda duration in nasal perception by manipulating the rime/nasal duration. Results suggested that, in merging contexts [ən] and [iŋ], participants’ nasal coda identification was indeed biased to different degrees by different rime/nasal durations, while in non-merging contexts [əŋ] and [in], their perception relied mainly on the vowel transitions.

論文貢獻：

本研究試圖初步梳理對台灣華語語者而言，在感知鼻韻尾差異時，各個聲學信號的權重。實驗一的結果與先前研究相符：基於構音上第二共振峰的轉變差別常已模稜兩可，導致它在感知上不足以作為分辨鼻韻尾的信號，即便在實驗刺激項中第二共振峰的差異十分明顯；至於在非開元音環境中的正確率偏倚的現象上，我們推測是因為合流的方向與合流的未完全導致辨識[iŋ]與[ən]時，比辨識[in]與[əŋ]時更易混淆，又於南台灣在/i/N的環境下，有另類的相反合流方向，因此某些南部受試者的[in]正確率卻較[iŋ]低。而就實驗二的結果，我們提議這個趨勢起肇於在合流環境中共振鋒轉變的對立已趨於模糊，使得受試者易受鼻韻尾音長的影響。綜合實驗結果，我們做出以下推論：（一）台灣華語語者在辨識鼻韻尾時可能漸漸把對共振鋒的依賴轉移到其他增強訊號(enhancement cues)上，及（二）這個感知上的轉變可能是從合流環境開始逐步發生。