As may be seen from data collected during language observations of four children over a period of two and a half years, children's sentences are not simply flawed versions of adult counterparts, but seem to result from a different grammar. These data indicate that logical formatives, such as "even," and "only," are sentence-initial constituents. They also point to interesting relationships between the structure of children's sentences with logical formatives and that of their negative and interrogative sentences. Children's understanding of these sentences appears to follow from a combination of phonological, syntactic, and lexical information. (JM)