This research project explores the language practices that emerged as a teacher taught a lesson designed to promote science literacy development for traditionally underrepresented students. This ethnographic study of a Detroit, Michigan, school examined the teacher's use of science language and its influence on students' use of science language. Using sociolinguistic discourse analysis, two modes of classroom language were identified. First, the teacher used a hybrid method of language involving her explaining science ideas by using vernacular and scientific language. This parenthetical type of speech, which we describe as "double talk", was also found in students. Second, students appropriated this same strategy for using science language in which they produced vernacular and scientific descriptions during explanations. The findings of this study are significant in their contribution to contemporary research about teaching and learning for minority students. These results implicate the need to teach science explicitly as a second language in urban classrooms. (Contains 1 figure and 12 tables.)