A study examined the English literacy development of English-Spanish bilingual students beginning formal transition into English literacy in a whole language classroom. The subjects were 26 Mexican-American third-graders. The curriculum had four components: theme-based literacy activities; teacher reading; free reading; and free writing. Instruction was meaning-focused and written language conventions were demonstrated through the use of contextualized mediations. Literacy growth was measured through pre- and post-reading miscue and retelling analysis, holistic and analytic writing analysis, and spelling assessments. Analysis of reading miscue data indicated statistically significant improvements in the students' ability to produce more meaningful sentences. Additionally, retelling analysis showed significant gains in the overall number of retelling units and matches produced by the students. Analytic writing analysis showed improvement in capitalization and spelling, and the in number of words produced in a story. Spelling improvement was also noted in an analysis of words produced in isolation. Holistic analysis of students' written stories did not indicate significant improvements, nor did analytic analysis show an increase in the number of sentences or the conventional use of punctuation. Results suggest that literacy development may require differentiated mediation, i.e. some tasks may require more direct mediation than others. (Contains 31 references.) (Author/MSE)