Acquisition of phonological variation in French In adult French phonology, schwa is a separate vowel category that either deletes or merges with /œ/ in the output. This thesis revolves around the distribution, categorisation and acquisition of schwa. We test two main hypotheses on the basis of Swiss French adult and child data: one, that schwa does not constitute a separate category in early child language, and two, that acquisition of schwa alternation, consonant sequencing and the reduction of non-prominent syllables are intertwined. The analysis of inter-adult judgement data show that the distribution of schwa and /œ/ is near-complementary. The implication for acquisition is that there are few indications in the input that output [œ] needs to split into two categories. The analysis of child-directed speech show that the rate of schwa alternation is lower than in inter-adult speech. The implication for acquisition is that the categorical distinction between schwa and /œ/ is blurred. The analysis of spontaneous and semi-controlled child language data show that children in all ages, from 2;03-3;05, prefer the output variant with schwa. Schwa alternation in spontaneous speech is rare, even in children who master consonant sequencing and syllable reduction. As for children who do not master these aspects of phonology, no spontaneous alternation is attested. In a semi-controlled setting, where the child is exposed to the variant without schwa, the older children, who master consonant sequencing and syllable deletion, are sensitive to the input and produce the variant without schwa. As for the children who do not master these aspects, sensitivity to the input is low. However, in the rare cases they do show sensitivity, they modify the target form in conformity with their grammar.