English as a second language is the utilization of English by speakers of other languages. Courses for English-language learners might be referred to as English as a second language (ESL), English as an foreign language (EFL), English as an extra language (EAL), or English for speakers of other languages (ESOL). English as a foreign language (EFL) is normally reserved for non-local English speakers learning English in a nation where English is not usually spoken. The term ESL has been confused by some to show that English would be of optional significance. The term ESL can be a misnomer for a few who have acquired other languages before learning English. The terms describing the learners can be Limited English Proficient (LEP), but more corrrectly, now, English Language Learners (ELL), and lately English Learners (EL), has been utilized. The students' home languages and cultures are viewed as critical to the learning process.

Bilinguals may have an advantage in the workplace over monolinguals as bilingual individuals can do tasks that monolinguals can't, for example, communicating with clients who just talk a minority language. A study in Switzerland has found that multilingualism is associated with an individual's pay, the efficiency of firms, and the gross household product (GDP); the researchers found that Switzerland's GDP is enlarged by 10% by multilingualism. A study in the United States by Agirdag found that bilingualism has significant monetary advantages as bilingual people were found to be increasing every year with more compensation than monolinguals.