A study of differential brain hemisphere involvement in second language acquisition is reported. The study examined the idea that the right hemisphere is progressively more involved the later the second language is acquired. Various techniques for monitoring hemispheric functioning are described, especially the Evoked Potential (EP) technique. In this experiment, EPs in response to unilateral visual presentation of words in two languages were recorded in three groups of individuals, categorized according to the age at which they acquired the second language (infancy, childhood, and adolescence). The results did not support the popular notion of progressively greater right hemisphere involvement. (Author/MSE)