| The purpose of the dissertation was to investigate English as a foreign language (EFL) students' use of their first language (L1) in composing English texts. The first study focused on factors associated with students' spontaneous use of L1 in EFL writing. The research questions of this study concerned how spontaneous L1 use in EFL writing may interact with cognitive demands of writing tasks, learners' English proficiency, and writing quality. Thirty Taiwanese college students from different disciplines participated. Writing tasks included the issue analysis and argument analysis tasks, both derived from GRE and GMAT writing. Students' percentage of L1 use in think-aloud protocols was calculated within each phase of the composing process and compared to the cognitive demands of writing tasks, students' English proficiency, and writing scores.; EFL students' percentage of L1 use was found to vary not only by cognitive demands of writing tasks but also by types of writing tasks. Total quantity of L1 use of EFL students was not related to their English proficiency. Further, EFL students' spontaneous use of L1 was found to be associated with better writing quality when used in activities such as making logical transitions, posing questions about logic and content development, or summarizing long chunks of reasoning.; The second study, concerning the advantage of L1 used as the only composing language in EFL writing, looked in detail at four cases to examine factors such as the cognitive demands of writing tasks, students' English proficiency, and students' ability to use L1 strategically. The choice of composing language was found to be associated with English writing quality only in cognitively demanding writing tasks, such as argumentation. In argumentation, the advantages of composing in L1 depended on the interaction of students' English proficiency and students' ability to use L1 strategically. Compared to English, L1 Chinese as a composing language was advantageous to writing quality when students had either the ability to use L1 strategically or high English proficiency. On the other hand, L1 as a composing language was disadvantageous to English writing scores when the student had neither the ability to use L1 strategically nor high English proficiency. Pedagogical implications are discussed. |
