經過四十年國語教育的推展，臺灣的國語今日已幾乎發展定型。現行的臺灣國語 與民國二十一年教育部公布的標準國語有相當大的差距。本文是以聲學的角度來描寫臺灣國 語八個單元音的語音特色，比較不同語族（閩語、客家、國語）臺灣國語單元音間的差異， 並與北京普通話單元音做比較。結果元音聲學圖顯示閩南語、客家語語族臺灣國語的元音均 受到母語的影響，與國語語族的元音在口腔中位置前後略有不同，客家語語族尤為明顯：客 家語語者元音的發音位置均比其他語族的元音位置還前。而臺灣國語和北京普通話的差異主 要是北京普通話的元音空間比臺灣國語的空間大，因此它的元音間彼此距離較大。 空韻的語音特性有舌尖元音、展唇後高元音〔□〕（謝國平， 1990 ）和高央元音〔□〕（ 黃金文，1994 ）幾種不同的說法，本文也從空韻舌位的 X 光照片圖、空韻的聲學特性，並 與日語展唇後高元音〔□〕、韓語的高央元音〔□〕的聲學特性做比較，來論證國語空韻是 個舌尖元音。

　　　　　After Mandarin education started in the 50's, Taiwan Mandarin is fixed today. Taiwan Mandarin is quite different from the Standard Mandarin that the Minister Education issued in 1932. This study investigated the 8 Taiwan Mandarin vowels from acoustic viewpoint. In addition to comparing the different vowel realizations of Taiwan Mandarin among three linguistic groups in Taiwan (Minnan, Hakka and Mandarin), the difference between Taiwan Mandarin and Peking Putonghua is also investigated. The results show that vowel realizations produced by Minnan and Hakka linguistic groups are affected by the vowel system of their mother tongue. For instance, in terms of vowel chart, vowels produced by Hakka speakers are fronter than those produced by Minnan and Mandarin speakers. The difference between Taiwan Mandarin and Peking Putonghua is taht Peking Putonghua's vowel space is bigger than that of Taiwan Mandarin, and the vowels of Peking Putonghua are more distant. Generally, Chinese Empty Vowel is regarded as apical vowel. However, Tse (1990) considered it as a high, back, unrounded vowel [ □ ]; while Huang (1994) considered it as a central unrounded vowel [ □ ]. Based on the Empty Vowel's X-radiography and its acoustic characteristics, the acoustic studies on Japanese [ □ ] and on Korean [ □ ], we argued that the Chinese Empty Vowel is an apical vowel.