This paper, based on Rosenbaum's (1967) grammar of adult English, attempts to apply ideas of deep structure and transformations to child grammar. The main rules predicated include phrase structure rules, segment structure rules, contextual features, and transformational rules. In this approach, the role of transformations is to segment and place elements into the string, rather than to change meaning. This process appears similar to what a child does as he learns a language. Lexical entries described by this theory can provide insights into what the child does with new forms. Rules suggested here are given, not as models of what a child has done, but as characterizations of it. By examining the functional load of transformations, a new measure is derived to capture syntactic complexity--that of mean transformations per utterance (mtu). This outline for writing grammars for children can capture generalizations about children's grammatical development that have previously been missed. The technique provides a basis for comparing data from several studies and for breaking down the unreplicable nature of most child language data. (CK)