This paper aims to first clarify how semantic redundancy occurs in L2 production due to the automatic substitution of an L1’s elements. The second goal is to argue that raising awareness of the features of one’s L1 in L2 learning is essential for preventing redundancy. The main focus of this analysis is the mechanical substitution of “I think” for “to omou,” which is frequently seen in Japanese university students’ written work. Unnatural errors caused by substitution are difficult to deal with due to deep-rooted factors ranging from grammatical disparity to confusion resulting from cultural differences. Cultural differences have not been explored in detail in the current context, although Nishitani and Nakazaki (2015) partially analyzed grammatical disparity. Explaining “to omou” and “I think” will reveal the factors that trigger the semantic redundancy mentioned above. Overall, this paper maintains that one of the key ways to prevent the L2 problems in question is to foster a deeper awareness of one’s L1.
