High Quality Content by WIKIPEDIA articles! Second-language acquisition or second-language learning is the process by which people learn a second language. Second-language acquisition (often abbreviated to SLA) also refers to the scientific discipline devoted to studying that process. Second language refers to any language learned in addition to a person`s first language; although the concept is named second-language acquisition, it can also incorporate the learning of third, fourth, or subsequent languages. Second-language acquisition refers to what learners do; it does not refer to practices in language teaching.