Modelling Learning Difficulty and Second Language Proficiency: The Differential Contributions of Implicit and Explicit Knowledge

This article re-examines the question of what makes some grammatical structures more difficult to learn than others, arguing that this question can only be properly understood and investigated with reference to the distinction between implicit and explicit knowledge of a second language. Using a battery of tests that were designed to measure implicit and explicit L2 grammatical knowledge of seventeen grammatical structures (Ellis 2005), learning difficulty in relation to these two types of knowledge was investigated. The results showed that structures that were easy in terms of implicit knowledge were often difficult in terms of explicit knowledge and sometimes vice versa and that, overall, there was no correlation between the rank orders of difficulty of seventeen grammatical structures for the two types of knowledge. A correlational analysis showed that the structures varied as to whether it was implicit or explicit knowledge of them that was related to a measure of general language proficiency. A regression analysis demonstrated that both types of knowledge predict general language proficiency.