This article reports on an ethnographic research project that investigated the relationship between home language use and acquisition of academic English as determined by the Comprehensive Test of Basic Skills (CTBS) scores. The subjects were 33 children ages 10 to 14 from bilingual Spanish-English families. Data on home language use was collected through interviews and taping, with variables including the type of reading and writing in Spanish or English and the language preference for family communication. Results indicated a strong correlation between children's ability to read in Spanish and scores on the CTBS reading and language tests, with no correlation between the amount of Spanish spoken at home and success on the CTBS tests. There was also a correlation between father's educational level and their children's CTBS scores. The findings of this study show that Hispanic children whose parents are monolingual Spanish speakers do better on school measures of academic English if the children maintain oral and written literacy in Spanish. (MDM)