A review of research was conducted on the possibility of a sensitive period for the acquisition of native-like pronunciation in a second language, as well as on related questions concerning the universality of this phenomenon, age factors, biological versus cultural origins, and developmental psychology. The review showed variation in studies and findings with regard to the age groups considered, nature of the pronunciation tests, and length and type of exposure to the second language. One conclusion drawn is that cerebral lateralization is likely to be irrelevant to mastery of accent-free speech in a second language, while age is a factor. Further research on adult second language acquisition is recommended, including examination of possible post-puberty psychomotor disadvantages, adult unwillingness to take risks, and identification with in- or out-groups through language proficiency. It is inferred that there is no innate psycholinguistic factor operating to prevent learning a second language with accent-free pronunciation as an adult, and that language teachers must attend to pronunciation accuracy as they would to accuracy in other aspects of language learning. (MSE)