The study of the spontaneous generation of a pidgin by two children, five and six years old, to accommodate their communication needs when neither had fully acquired his native language, is described. The children were an African native of a Swahili-speaking family and an American child living in the African village. The new language created was a mixture of Swahili and English but distinct from both, unintelligible to any but the two, and the primary language for both children for most of their daylight hours for a period of fifteen months. The pidgin is analyzed from the American child's comments on and translations of tape recordings of a variety of interactions. Directions of linguistic change and elaboration typical of creolization were found. The language is described in terms of its elements from Swahili and English, lexical content and development, an ethnographic view of the social context of the pidgin, the village speech community, children's speech community, and functions and uses of the pidgin. Comments are made on verbal play and the process of invention in language, and on the universal characteristics of both children's language and pidgin language. Transcribed conversations and data on specific word use and utterances are used as illustrations. (MSE)