Phonologists and psycholinguists have described in great detail the structure of phonological representations, the rules (or computations) operating on them, and the various levels of representation and processing that must be involved in speech perception and production. That area has been reviewed before in relation to dyslexia (Ramus, 2001). Here we only recall the overall cognitive architecture that we assume (Figure 8.1) and will explain phonological and psycholinguistic concepts where they are necessary to understand our experiments.