HSIEH, Kuo-Pin (Hsing-Kuo University) The newly developed linguistic traits as an ethnic boundary for the dying Sirayan Plains Aborigines in Taiwan This paper aims to present and expound the fieldwork findings about how the so-called vanishing Sirayan Plains Aborigines in Taiwan, with an extinct mother tongue, persist in drawing distinct ethnic boundaries because of their newly developed linguistic traits. The Sirayan Plains Aborigines have been widely viewed as an ethnic group that had lost its distinct ethnic boundary since the Sirayan language became extinct in 1908. However, according to my fieldwork conducted in two documented Sirayan villages, I found that many highly sinicized Sirayan descendants still maintain Sirayan identification and the Sirayan-Han ethnic boundary still persists in several aspects, including a set of linguistic traits developed over the past decades. All contemporary Sirayan descendants have used Minnan (southern Fujienese) as their mother tongue, but some elderly still speak Minnan with a distinctive accent, which usually consists of a heavy ending tone in each sentence. Aside from this, many Minnan terms with the prefix "hoan," [barbarian], signifying derogatory meaning against aborigines, are modified or forbidden in these villages. Under the circumstances that the Sirayan-Han boundary has become blurred, these newly developed linguistic traits serve as a new dimension of ethnic distinction for the local people to tell the difference between Sirayan people and Han Chinese.