Second language acquisition research focuses on the process by which individuals learn or acquire a second language after already knowing one language. This field of study explores factors that can influence language learning, such as age, motivation, language input, and individual differences. Researchers also investigate different methods and approaches to teaching a second language effectively. This research area is interdisciplinary, drawing on theoretical perspectives from linguistics, psychology, education, and sociology. Overall, second language acquisition research aims to understand how individuals can develop proficiency in a new language and to improve language learning outcomes.