This is a basic, non-specialist introduction to the study of how people learn languages. The author brings together the diverse insights of linguistics, psychology and education, assuming no prior knowledge or training in these fields. The author addresses the learning of languages at different ages and in different circumstances, including first language acquisition, second language acquisition, school language learning and childhood bilingualism. Comparison is made of naturalistic and tutored learning, and language learning is also examined in the special circumstances of deafness, childhood isolation and mental disability. Other topics include the influence of culture and personality on language learning, individual differences in the learning of languages, and the nature of the good language learner.