L1⁺ approach is a novel methodology for ELT, which attempts to maximize the benefit of L1 knowledge for L2 language learning. This paper attempts to verify the mechanisms and efficacy of the L1⁺ approach by discussing the concept of L1⁺ language, which consists of L1 language in the word-order of the target language, and critically comparing it with other conventional approaches of teaching English grammar in Japan. The analysis suggests that the L1⁺ approach has a prospect of better facilitating sentence productions, compared to other conventional Japanese approaches.
誠一 中山 (Sat,) studied this question.