The spontaneous speech of a six-year-old bilingual child was analyzed for this study. The child has lived in the United States and English is her primary language but her parents speak only French in the home and she has spent several months in France during three visits there. The data used in this study were collected in the child's home by her bilingual parents during the period when she was six years and three months to seven years and two months of age. Grammatical and lexical interference was shown to occur in both languages: English influencing French in word order and stress, and French influencing English in the category of gender. The child does not, however, show any evidence of phonological interference in either language. Examples are given of the use of loanshifts, loanwords, syntactic substitutions, word order, agreement of gender and number, stress, and extension of grammatical morphemes. The author concludes that, in spite of considerable lexical and grammatical interference, there is no evidence of a merger of lexicons or grammatical structures. The child has not evolved a lexicon or grammatical structure compounded of French and English elements. The author also feels that these observations illustrate the validity and completeness of the theoretical framework developed by Uriel Weinrich in "Languages in Contact" (New York, 1953). (JD)