本研究目的，一是確定台南地區閩南語元音位置，二是探究閩南語與華語雙語人元音位置是否互相影響，若有，其影響是否存在年齡與性別差異。透過收錄語料的共振峰繪圖，確認台南閩南語中元音音值為e、ə、o三分。整體而言，台南華閩語元音分佈相互影響，單元音與複合元音系統的變化存在年齡層差異。老年層以閩南語元音組合為主軸，閩南語/o/、/oo/對比以前後差異為主，但華語ou位置仍未確立；同一前後的華語上升與下降複合元音無區別，如ei與ie混。年輕層的華語音韻確立，華語元音位置穩固，複合元音區別確立；ie、uo過渡明顯，ei、ou仍偏向單元音。本研究透過華閩元音對比與年齡層區別分析，清楚呈現雙語元音系統交互影響的方向與先後差異，並進一步以語言優勢與元音分布理論解釋。

This study aims to clarify the relevant placement of vowels in Tainan Minnan language, and figure out whether the vowel distribution and combination constraints of different languages would have effect on each other. And would age or gender be a variable? Drawing the vowel distribution with F1 and F2 data of 16 informants, we have shown in the paper that mid vowels in Tainan Minnan language should be 'e, ə, o'. In general, the two vowel systems of bilingual speakers tend to have influence on each other, and there is an age difference in the distribution and combination of Mandarin vowels. For the elder, the placement of Mandarin 'ou' rime varies, and there are no distinction between 'ie' and 'ei', and also between 'uo' and 'ou'. For young speakers, their Mandarin vowel systems are relatively stable, and the distinctions among different diphthongs are preserved well too. With a contrastive analysis of Mandarin and Minnan vowel systems of different generations, we exhibit the directions and orders of influence of one language upon the other, and give a further explanation with theories of language contact and vowel contrast in the paper.