本研究有兩個研究問題：1.台語/o/音素這三種主要讀音的競爭關係，以及世代與區域的分布狀況為何？2.台語/o/音素的讀音，未來可能如何發展？本研究共有112 位發音人，其中包括51 位老年組發音人及61 位青年組發音。所有發音人皆以台語為其母語（之一），發音人以台語朗讀一份設計過的詞表。詞表朗讀的語料及發音人的地區分布的分析結果顯示，老年世代發音人的讀音相當穩定， [o]元音穩定存在，且主要呈現南[□]北[o]的分布，中部地區則是[□]、[o]皆有，且勢力相當。至於青年世代則顯得相當不穩定。大部分發音人皆未穩定保有[□]、[o]、[□]當中任何一種讀音，且大多在[]及[]之間選擇，青年組發音人的[o]元音和老年組相比，已大幅減少。至於台語/o/音素的讀音未來可能如何發展? 本研究的結果顯示，[□]、[□]並存應該會是台語/o/音素未來主要的發展，且多項分析結果皆顯示，這兩個元音的勢力相差不大，呈現勢均力敵的狀態。另外，本研究的結果，無論是誤讀音、[□]/[o]元音的選擇、[o]元音逐漸消失等，都顯示在台灣目前華語強勢且台語第二語言化的情況下，台語的語音變化或發展，似乎越來越難以排除華語的影響。

This study has two research questions: 1. What are the current status of the three competing sounds of Taiwanese /o/ phoneme, their generational distribution and the regional distribution? 2. How is the Taiwanese phoneme /o/ likely to develop in the future? 51 old and 61 young native Taiwanese speakers participated in this study. Speech data were collected through wordlist reading and were analyzed generationally and regionally. The results indicated that the old speakers stably pronounce the phoneme /o/ as either [o] or [□], with the former mainly observed in the northern Taiwan, the latter southern Taiwan, and the mix central Taiwan. As to the young generation, most of the speakers pronounced the phoneme /o/ as either [□] or [□] in a various and unstable manner; the frequency of the vowel [o] was largely reduced. Among the stable young speakers, who accounted for less than 40% of the young speakers in this study, the vowel [□] prevails in southern Taiwan and the vowel [□] north. As to the development of the pronunciation of the phoneme /o/, this study has two predictions. First, both [□] and [□] will remain as the major pronunciations as currently neither demonstrates any obvious dominance. In addition, Mandarin as the most predominant language in Taiwan, will inevitably plays a role in the sound variation of Taiwanese.