Children's awareness of grammar can be traced in the way they use and particularly mis-use morphology and constructions in what Clark (2001) calls 'emergent categories'. We focus our longitudinal study on a French speaking child's use of possession markers (Anaé), and her creative deviant productions (la poupée de moi for ma poupée/my doll). We make a detailed analysis of her to and fro meanderings between a global strategy thanks to which she locates, identifies and uses whole blocks or constructions without analyzing them, and a more analytic strategy that parallels her progressive mastery of the semantic and syntactic complexity of grammatical morphemes.