Grammatical complexity of English textbooks: A comparative study of two book levels: Elementary and Pre-intermediate

Textbooks are considered the backbone of education. They serve as the main teaching tool in the curriculum, having great impact on teaching and learning and effectively contributing to the improvement of educational quality (Besser, Stone, & Luan, 1999). Choosing an appropriate textbook for a course in the diversified English Foreign Language (EFL) textbook market has become harder (Minoo & Nikan, 2012). This study investigates linguistic complexity in English textbooks used in the teaching of English as a second or foreign language to speakers of other languages. It employs systemic functional grammar as the main theoretical framework to examine grammatical features in reading passages. The focus of the study is the investigation of the four grammatical features which are considered the typical complexity of written language namely, lexical density, nominalisation, Grammatical metaphor and thematic structure (Halliday, 1985a, 1985b, 1994; Halliday & Matthiessen, 2004, 2014). The presentation reports on findings of an on-going Ph.D research on linguistic complexity in two English textbooks at elementary and pre-intermediate levels. The results will provide criteria in choosing English texts or textbooks, which are based on the grammatical features.