Current opinion regarding the nature of the young child's representation of two or more languages is that there is one system during the earliest stages of development. This paper explores theoretical and methodological difficulties underlying this issue. Theoretically, it is questioned what is being claimed about the child's cognitive capacities for language when one versus two systems is discussed. Methodologically, there is the problem that the young bilingual will be limited to a basic phonetic inventory which makes the child appear to have one system. The study pursues the issue of one system versus two by analyzing the acquisition of Italian and English by a young girl L, age 2;0. Results show that L's segmental inventories, but not syllables, were very similar for the languages. In Italian, L used a majority of multisyllabic open syllables, as do some children learning English as a first language. This pattern did not carry over to L's English, which was mostly monosyllabic with closed syllables. These results suggest that L was using separate systems in her phonological development. One needs to be cautious about proposing strategies for phonological development independent of the adult language being learned. L appeared to use opposing strategies for English and Italian. (JK)