The contribution of cognitive event-related potentials (ERPs) and particularly of the N400 component to the study of language processing is considered. After a general presentation of the various components of cognitive evoked potentials which are differentiated from early potentials (sensitive to perceptive parameters), the neurophysiological and psychological correlates of ERPs are discussed. Before the presentation of the main studies concerned with the correlation between specific late components and linguistic processes, it is proposed an introduction to some theoretical models of language processing which serve as conceptual framework supporting most of the experimental approaches in this field. The results of EPs studies devoted to functional asymetries in language processing are briefly mentioned. Then a number of studies are analysed, these demonstrate the sensitivity of event-related potential measures to linguistic manipulations. Finally, the studies concerned with the N400 are reviewed, this potential appears to be the more specifically language-related ERP component, even if its connection with specific linguistic processes or its differentiation from N200 are still under debate. Nevertheless language-related electrophysiological investigations may become in the near future a useful complementary approach to our understanding of language processing and language disorders.