A large number of factors are considered in their role in second language learning. Individual factors include language aptitude, personality, attitudes and motivation, and the role of the speaker's native language. Teacher factors involve the method of instruction, the sex of the teacher, and a teacher's training and competence, while sociocultural factors include the degree of urbanization, nationality, and socioeconomic status. Following a review of relevant literature, a study conducted in Sweden is described. During the spring of 1966, questionnaires were sent to local government school authorities in Sweden to determine how many, if any, immigrant children were receiving special instruction in Swedish, and to obtain information concerning the sex, nationality, place of emigration, and the father's occupation. A battery of tests were then sent out. Six language tests covered pronunciation, dictation, oral comprehension, reading comprehension, free written composition, and free oral composition. Three intelligence tests were administered, and teacher attitudes were sampled. Results show sex differences in favor of girls. Teacher competence and students' age seem to influence second language learning to a significant degree, while the speaker's native language and socioeconomic status have less importance. (CHK)