The question of why some second language learners are more successful than others is examined from two different approaches. One looks at the social distance between the speakers of the target language and the learner's native language and, on one hand, the resulting learner and target-language-speaker attitudes and, on the other hand, the type and amount of input that the learner receives. The second approach takes the perspective of the differences between first- and second-language learners and between the processes by which language is learned. With regard to the "social distance" approach, the following aspects of English language learning are discussed: pidgins and pidginization; pidginization and second language acquisition; depidginization (gradual approximation of standard English); input and second language acquisition; foreigner talk; and the concept and role of social distance. In relation to the "fundamental distance" hypothesis, one researcher's findings about differences in adult and child language learning processes (lack of guaranteed success, variation in degree of success, variation in goals, fossilization, importance of instruction, and role of affective factors) are highlighted, and the strong influence of first language knowledge and general problem-solving systems is emphasized. The two approaches are found to be different but not contradictory, and further research is recommended. (MSE)