客語兒向語與成人語單、雙元音聲學比較研究

AN ACOUSTIC COMPARISON OF MONOPHTHONGS AND DIPHTHONGS BETWEEN HAKKA INFANT-DIRECTED AND ADULT-DIRECTED SPEECH

本研究針對客語兒向語與成人語單、雙元音進行聲學比較，選取十組母嬰配對為參與者，並以11個常用雙音節詞為研究字表。本研究利用PRAAT分析每個目標音節的3個清晰樣本的第一與第二共振峰數值，並將共振峰數值標準化為巴克值，最後以巴克值繪製元音走勢圖及計算元音聲學參數。本研究分析結果如下：（一）兒向語裡單、雙元音均有延長。（二）與成人語相比，兒向語的單元音格局下降，元音空間面積略為縮小，元音聲學距離縮短。（三）與成人語相較，兒向語雙元音的時長變長，元音聲學距離較長。（四）兒向語維持與成人語相似的聲韻比有助於嬰兒的音節概念形成與後續音韻覺知能力的發展。

This study acoustically analyzed monophthongs and diphthongs in Hakka infantdirected speech (IDS) and adult-directed speech (ADS). Ten mother-infant dyads joined this study. The speech stimuli included eleven commonly-used disyllabic phrases, the first syllables of which were the target words. This study selected three clear tokens from each disyllabic phrase, and used PRAAT to measure the values of the first and second formant of all samples, normalized formant values into Bark values, and used Bark values to draw the vowel space of monophthongs and the trajectories of diphthongs, and to count vowel-related acoustic correlates. The results were stated as follows. First, monophthongs and diphthongs in IDS became longer than those in ADS. Second, as compared with ADS, IDS displayed a downward-moving vowel space, a slightly shrinking vowel space area, and shorter acoustic vowel distances. Third, as compared with ADS, IDS showed longer duration and longer acoustic distances in diphthongs. Fourth, the similar onset-rime percentages in both IDS and ADS are helpful for infants to create the concepts of syllables and cultivate the ability of phonological awareness later.