Attempts to characterize and contrast aspects of functional organization of neuropsychological systems carrying out primary language acquisition and two types of nonprimary language acquisition: secondary language acquisition and foreign language learning. There appears an intrinsic neurofunctional basis for the greater facility of young children…

The modified stage hypothesis, which predicts the balance of right v. left hemisphere involvement in learning or acquisition of languages, is examined and an apparent contradiction is found between conclusions from experimental findings supporting the hypothesis and Krashen's Monitor theory underlying it. (MSE)