Abstract
This chapter provides analysis of the interlanguage of second language learners and the pedagogic implications. It begins with reviews of the concept of interlanguage from the background of cross-linguistic influence, providing analysis of interlanguage of second language (SL) learners, proof of systematic variability of interlanguage use at the syntactic level as well as implications for SL teachers. It discusses the revised interlanguage hypothesis, revealing the shift from the previous concept where interlanguage solely applied to adults acquiring second languages to children who produce interlanguages with socio-linguistic justifications. This study highlights the role of social contexts in interlanguage development. Finally, the study reviews the concept of fossilization, causes of fossilization, and the arguments on inevitability of fossilization in second language learning. Pedagogically, the chapter suggests that interlanguage system can be changed by employing different teaching methods and strategies, creating linguistic and social contexts which are facilitative, and delisting those that inhibit learning and classroom achievements.