Characterization of Auditory Processing Involved in the Encoding of Speech Sounds

Inclusion Criteria: For all subjects: * native French speaker * no medical treatment for behavior or neurological disorders * normal or corrected vision * right-handed * normal otorhinolaryngology examination * valid affiliation to social security * no participation to another research study For the normal-hearing subjects * normal tonal hearing thresholds * normal tympanometry For the subjects without specific language impairment * aged from 6 ro 40 * normal school attendance without scholastic retardation * normal intellectual level * normal for age reading skills * no delayed speech (expression \& production) For the children with specific language impairment * aged fom 8 to 18 * persistent specific literacy difficulties with reading levels at least 18 months behind that of their peers * normal intellectual level For the hearing impaired subjects * age from 18 to 70 * first auditory rehabilitation * bilateral and symmetric hearing loss (±10 dB) with hearing thresholds between 0 and 25 dB at 0.25 kilohertz, 0 and 35 dB at 0.5 kilohertz, 0 and 50 dB at 1 kilohertz, 25 and 70 dB at 2 kilohertz, 25 and 80 dB at 3 kilohertz, 30 and 80 dB at 4 kilohertz Exclusion Criteria: * non signed assent * treatment for depression, epilepsy, Parkinson's or alzheimer's disease during more than 6 months * physical health deficiency * mental retardation * neurological or psychiatric disease incompatible with testing procedure For children * known problem of hearing loss or chronic middle ear disease whic compromized the hearing status * schooling in a foreign language * foreign language spoken at home with both parents