Relating Developmental Progression Index of Grammatical Complexities to Cefr Proficiency Levels

Linguistic studies which have practical benefits to language teaching seldom draw proper attention from language professionals. The developmental progression index of grammatical complexity (DPIGC) proposed by Biber, Gray and Poonpon (2011) is no exception. They proposed the index based on corpus analyses of two registers, speech and writing. Used in language teaching, this evidence-based index would enable teachers to see learners’ development in grammatical competences necessary for reading and writing in academic contexts. Despite its great potential, the DPIGC is not widely adopted or used by language professionals. The index may be less accessible because its scales are relative only within the index itself and not related to more globally accepted proficiency levels in language teaching. This paper related each grammatical structure in the DPIGC to those in the English Grammar Profile (EGP). It revealed that grammatical features that are much more frequently used in academic prose than speech do not have any corresponding structures in the EGP, not even at the C1 and C2 levels, while those more commonly used in speech do. Given that the EGP is based on the corpus of L2 English learners’ writing scripts, the result indicates L2 English learners are not competent users of distinctive grammatical features of academic prose and suggests the necessity of instruction of these features.