this work examines the mechanisms and representations underlying the production of words with several pronunciation variations. A process of phonological variation is studied in particular: the French schwa. The results of phonetic and psycholinguistic studies suggest that variations without schwa do not result from a process of phonetically reducing the vowel or from a phonological rule of erasure. They show that the words with schwa have two lexical representations, one per variant. That conclusion applies to words in which both variants are used and to words produced with a single variant, the unused variant of which corresponds to the spelling of the word or is frequently understood in the speech of others. The data also suggest that the lexical representations used in production are abstract. These results lead the author to propose a psycholinguistic model for the production of words which incorporates the pronunciation variants.