To test between two recent accounts of the early stages in the acquisition of negation, we conducted an elicited production study with 25 children, between 2;05 and 3;04 (mean 2;11). The experimental study produced a robust set of negative sentences, with considerable individual variation. Although 13 of the child participants mainly produced adultlike negative sentences with doesn’t, 12 children produced nontarget forms. The nonadult productions included medial negation structures, both with bare verbs (It not fit) and with inflected main verbs (It not fits, It don’t fits), as well as negative sentences with “high” inflection (It’s not fit) and doubling (It’s not fits). Although some of the findings are consistent with the account advanced by Harris & Wexler (1996), their prediction that negative sentences with do-support (It don’t/doesn’t fit) co-occur with medial negation and a bare verb (It not fit) was not borne out. The findings are amenable to the account advanced by Thornton & Tesan (2013), who contend that children’s grammars are initially restricted to adverbial negation. Children’s nontarget productions with the 3SGS morpheme positioned on the main verb or in Infl are attributed to a nonadult mapping between syntax and phonological form (PF). The steps children take to converge on the adult mapping are explained by invoking the theory proposed by Adger (2003).