The role of two L1s in L3 English writing

Abstract The study investigates morphological and syntactic interference errors in L3 English writing production by Acehnese Indonesian adult bilingual learners who acquired Acehnese and Indonesian simultaneously in childhood. In particular, the study looks at which language (L1 Acehnese or L1 Indonesian) is dominant in transferring morphological and syntactic errors in L3 English writing. A qualitative descriptive method was used using open-ended questionnaires, students’ essays, and semi-structured interviews. The study was carried out in one of the public universities located in Aceh province, Indonesia. The participants were undergraduate students enrolled in a paragraph writing course at the university. The finding showed that L1 Indonesian appears to play a more significant role than L1 Acehnese in L3 English writing acquisition. L1 Indonesian causes more errors than L1 Acehnese in L3 English writing of Acehnese Indonesian adult bilingual learners. Indonesian becomes a language of thought for learners when writing in L3 English.