Many recent studies concerning language use in Taiwan, have observed that in the Minnan speaking communities quite a few signature linguistic features,characterizing Zhangzhou against Quanzhou, two major sub-dialects of the Minnan, are no longer distinguished and there emerges a new mixed variety. One noticeable phonological example is that the distinctive rime /uĩ/ of Zhangzhou,originally prevalent in Jiaoxi, Yilan and Daxi, Taoyuan, has been replaced with /ŋ/,particularly by most of young Minnan speakers. This paper not only gives a full account of that kind of phonological changes but also many lexical items in the new variety. In addition, it compares and contrasts the emerging variety with the Xiamen dialect, another recently koineized variety on basis of the Zhangzhou and Quanzhou sub-dialects spoken in Mainland China, in the attempt to find out how the speed of linguistic changes are correlated with societal conditions and speakers’perception of the functions of the varieties involved.