A case study investigated the emergence of language and language concepts in a bilingual child, a girl aged 16 months to 6 years, 7 months. Observations were made by the child's parents and relatives in the child's home where the mother spoke Finnish and the father English. The report summarizes developments in phonology, morphology, word-level semantics and reference, and interpersonal discourse and offers illustrations for unelicited data and observation. It is proposed that metalinguistic conceptualization occurs when a cognitive problem is encountered. The role of bilingualism in the process of concept formation is examined. The data are especially rich in phonology and a correspondingly detailed analysis of this area is made. It is concluded that overt linguistic awareness was considerable and was focused on the word in grammar, the distinctive feature in phonology, on conversational interaction in discourse, and homonymy in semantics. Syntactic awareness was not apparent. Bilingualism appeared to contribute directly to concept formation in the areas of phonology, morphology, and the distinction between word and referent. Additional patterns are examined. (Contains 49 references.) (MSE)