This article introduces a model of classification of phonemic and phonetic negative- transfer based on an empirical study of Turkish-English Interlanguage. The model sets out a hierarchy of difficulties, starting from the most crucial phonemic features affecting “intelligibility”, down to other distributional, phonetic, and allophonic features which need to be acquired if a “near-native” level of phonological competence is aimed at. Unlike previous theoretical studies of predictions of classification of phonemic and phonetic L1 interference (Moulton 1962a 1962b; Wiik 1965), this model is based on an empirical study of the recorded materials of Turkish-English IL speakers transcribed allophonically using the IPA Alphabet and diacritics. For different categories of observed systematic negative- transfer and their avoidance of getting “fossilized” in the IL process, remedial exercises are recommended for the teaching and learning BBC Pronunciation. In conclusıon, few methodological phonetic techniques, approaches, and specifications are put forward for their use in designing the curriculum and syllabus content of teaching L2 pronunciation.