The enhanced metalinguistic abilities demonstrated by additive-bilingual children, including superior control of cognitive processing, may promote the development of symbolic reasoning. Children educated in additive-bilingual (immersion) settings may maintain normal native-language development, while acquiring a second language. This study compared 15 children in a Spanish immersion class with 15 children from a standard classroom over the course of three observations during second and third grades. Program type (immersion verses standard) was the independent variable in two comparisons, with nonverbal problem-solving as measured by the appropriate form of Raven's Matrices as the first dependant variable and native-language development as labeled by the Peabody Picture Vocabulary Test-R (PPVT-R) as the second dependent variable. For nonverbal problem-solving, an independent samples t-test on the mean gain in rank revealed significant differences in favor of the immersion children at the third observation, supporting the previously reported results of the second observation. A MANOVA applied to the PPVT-R scores over the three observations revealed no significant differences. The outcomes support the role of bilingualism in the development of symbolic reasoning among children in the early stages of bilingualism, and Lambert's notion of "additive-bilingualism." (Author/JL)