The aim is to discover particular factors which characterize the learning approach of bilingual children. Previous research by the principal investigator on a sample of Hebrew-English bilingual children from highly educated and verbal families indicated a distinctive pattern of cognitive strengths and weaknesses for these bilingual children as compared to monolinguals similar in age, sex, background, and intelligence. The procedure to be used will apply those tests which indicated distinctive bilingual performance in the earlier study to a sample of Spanish-English bilingual and monolingual children from relatively deprived economic levels. These tests will be supplemented by additional tests to ascertain more closely the particular cognitive factors on which these bilinguals may differ from monolinguals. The ultimate practical aim is the development of curricula, teaching methods, and materials to take advantage of the distinctive approach to knowledge acquisition and the particular strengths characteristic of the bilingual child. The theory behind expectation of acceleration in certain areas of cognitive development for bilinguals is that the experience of coping with interlingual interference creates acceleration in ability to understand language as a system and perhaps systems generally. The experiment provides for determining under what environmental conditions such acceleration effects may occur for bilinguals, e.g., whether it occurs in situations where bilingual children do not have the option of avoiding interference by ignoring or devaluing one of the languages or else by separating the languages according to distinct contexts of acquisition and usage.