The production of speech is a complex cognitive activity, whose elaboration may be disturbed in various ways. Our purpose here is to explore the continuum between normal and pathological speech production. There are similitudes between performance errors by average speakers and the paraphasias produced by aphasics in the same circumstances; both kinds of perturbations affect the same linguistic units and reveal similar psycholinguistic mechanisms. Yet, production in these two cases differ according to several criteria, such as the error rate, the way the erroneous item and the target item are connected, the speaker's awareness of inadequacy, the comments he makes and his need for justification. Those elements point out to the boundaries that may be defined between normal and pathological speech.