This dissertation studies the French adverb autrement, through its three main uses : adverb of manner, connective denoting negative hypothesis, and topic shifter. The importance of anaphora resolution and discourse structure is stressed. After a review of the literature on discourse structure and on the adverb, the characteristics of the three uses are defined thanks to spoken and written corpora, showing how context is instrumental in retrieving the antecedent and how the adverb relies on discourse and builds it at the same time. Already in the adverb of manner, anaphor and right scope are crucial in the construction of meaning. With the connective, referential relations leave room for logical relations holding from proposition to proposition, whereas the topic shifter is a metalinguistic use handling abstract discourse entities. A core of meaning [anaphor and negation] is identified, common to the three uses and accounting for bridges between them. This synchronic study is then used to reconstruct the adverb's grammaticalization, detailed observation in the present counterbalancing sparse historical data. It is shown that the notion of a construction, i.e. the use of the adverb in some context, has made evolution possible : in particular, word order in Old French was crucial, allowing the adverb of manner to occupy the initial position where reanalysis could occur ; the use of conjunctions also favored the emergence of some of the adverb's meanings.
