They are betwen nine and ninety years old, and even though they have been to school, they do not know how to read or write. Sometimes even their mouth articulates words they do not understand. Yet, no disease, no accident has damaged their intelligence. Their suffering is elsewhere: they are language-sick. Gisèle Gelbert explains in detail the scheme of linguistic functions, which she has elaborated, the history of the pathologies she has encountered, the method of reeducation she has imagined and experimented.