Children acquiring French elaborate their early verb constructions by adding adjacent morphemes incrementally at the left edge of core verbs. This hypothesis was tested with 2657 verb uses from four children between 1;3 and 2;7. Consistent with the Adjacency Hypothesis, children added clitic subjects frst only to present tense forms (as in "il saute" "he jumps"); modals to infnitives (as in "faut sauter" "has to jump"); and auxiliaries to past participles (as in "a sauté" "has jumped"). Only after this did the children add subjects to the left of a modal or auxiliary, as in "elle veut sauter" "she wants to jump", or "elle a sauté" "she has jumped". The order in which these elements were added, and the development in the frequencies of the constructions, all support the predictions of the Adjacency Hypothesis for left edge development in early verb constructions.