The meaning of children's lexical innovations is distinguished from the forms they rely on to convey meaning. Children require knowledge of the context in order to judge how the meaning of their innovation can be conveyed to the addressee. This contextualization is often achieved by default, since children tend to limit their early conversations to the here-and-now. Learning to assess what the addressee does and does not know is one factor children must attend to as they acquire the conventions of innovation. The word forms of lexical innovations seem to be acquired in a predictable order, with productive forms being mastered earlier. Children also attend to the semantic coherence of the new forms they are constructing, and regularize the lexical paradigms. This results in choosing, for instance, a single form for all agent nouns. Other principles also operate in the acquisition of the word formation rules for a language. (Author/JB)