Perspectives of the field of psycholinguistics and second language research are examined to provide a broader understanding of language learning and language behavior. Psycholinguistics, which uses the approaches of psychology and linguistics is defined as the search for an understanding of how humans comprehend and produce language. Based on the view that language can be examined at different hierarchical levels (psycholinguistic plan levels) and that the lower levels can affect higher levels, research findings for the following levels are examined: (1) phonology; (2) morphology; (3) lexicon; (4) syntax and sentence comprehension models; (5) syntax and language acquisition; (6) discourse and sentence syntax; (7) discourse and communication; (8) input/interaction and language development; (9) individual factors--age; (10) neurolinguistics and bilingualism; and (11) cognition, cognitive strategies, and language acquisition. By attending to factors related to second language acquisition, questions not covered in the psycholinguistic literature are discussed that may support linguistic rules or descriptions of language. While much of the review research primarily represents the reductionist school, unified explanations have also been addressed. The text may be appropriate for use in methods courses. (SW)