This paper accommodates EIL(English as an international language) together with EFL in English pronunciation teaching and learning. In recognizing EIL, I suggest three strategic levels for phonological norms in assessing leaners’ pronunciation: the level P(phonemic) as a mandatory level to achieve, the level NLA(native language accent) as a cautious level to suppress the native accent, and the level TLA(target language accent) as a desirable level to accomplish a "native-like" accent. After probing the significance of each level, the paper addresses the issue of learning patterns depending on different proficiency levels, together with the effect of formal instruction. The sounds under investigation are English /l/, /r/, and /si/ for the level P, Korean Nasalization and Lateralization for the level NLA, and English /p, t, k/ for the level TLA. Two groups of local college sophomores served as experimental subjects, one as an intermediate group and the other as beginners group. The correctness rate for each level turned out to be the level TLA the lowest(14.21%～ 22.22%), the level NLA the next (49.37%～57.95%), and the level P the highest(66.47%～74.08%). The level TLA achieved the highest effect of formal instruction(13.30%), and the other two levels achieved less effect(5.69%～5.79%). In the level NLA, three factors that affect native interference are suggested: familiarity, syntactic distance, and the length of previous vowels. It is argued that the lowest correctness rate of the level TLA is less alarmimg than the low number indicates, while the level P is more demanding to overcome regardless of the highest correctness rate in regard to effective communication in English.