This longitudinal study examined the association between early patterns of home language use (age 4.5 years) and vocabulary growth (ages 4.5 to 12 years) in English and Spanish for 180 Spanish-speaking language minority learners followed from ages 4.5 to 12 years. Standardized measures of vocabulary were administered to children from ages 4.5 to 12 years, and home language use was assessed via parent survey at study entry. Three predominant home language use patterns were identified: mostly Spanish, equal amounts of Spanish and English, and mostly English. Individual growth modeling results demonstrated initial English vocabulary differences between the three language groups, with the "mostly English" group outperforming the other two language groups. However, the rate of growth for the "equal amounts" and "mostly Spanish" groups surpassed that of the "mostly English" group; by age 12 years, the gaps among the 3 groups had narrowed, but participants' vocabulary skills remained below national norms. In contrast, students' patterns of Spanish vocabulary growth did not vary, resulting in parallel but widening gaps through age 12 years. Results suggest that early Spanish use in language minority learners' homes, in and of itself, does not interfere with the development of English vocabulary. However, despite their English instructional context, all learners' vocabulary knowledge was below average and the gap compared with national norms persisted. (Contains 3 footnotes, 5 tables, and 1 figure.)