Elementary writing instruction is often limited, mainly focused on personal narratives. Informed by Systemic Functional Linguistics, this article reports on the writing of grade 3-5 bilingual children in a variety of genres. Analysis of their use of first, second, and third person provides insight into their understanding of genre and audience. The results suggest that although students made successful attempts at writing in a variety of genres, they did not have full understanding of the purposes of those genres, and their understanding of the connection to audience was still in development. For Spanish-speaking newcomers, Spanish and English influenced each other. The study of a specific grammar point such as use of person offers deeper understanding of students' writing development, indicating that challenges in choice of grammatical person are rooted in factors such as understanding genre (purpose) and tenor (audience and voice). Implications for instruction are suggested. (Contains 1 figure and 4 tables.)