One of the most frequently used oral production facilitation techniques in the fields of aphasiology and psycholinguistics is phonological cueing. It consists of providing the speaker with a syllable or a phoneme which overlaps with the target word (usually a word onset, e.g., /do/ or /d /for “dauphin” - dolphin) before the presentation of the picture to be named. While this technique is widely used in neurolinguistics, the mechanisms underlying the facilitation of oral production by phonological cueing remain unknown. In this thesis we are investigating: 1) the mechanisms underlying phonological cueing effects in healthy and aphasic speakers using behavioral and electrophysiological methods. More precisely, we are testing whether facilitation by cueing results from cue effects on lexical retrieval and/or from phonological encoding processes, and 2) potential sources of variability in obtaining phonological cueing effects (modality of the cue, severity of the aphasia and its underlying deficit).