Teaching English as a foreign language (TEFL) refers to teaching the English language to students with different first languages. TEFL can occur either within the state school system or more privately, at a language school or with a tutor. TEFL can also take place in an English-speaking country for people who have immigrated there (either temporarily for school or work, or permanently). TEFL teachers may be native or non-native speakers of English. Other acronyms for TEFL are TESL (Teaching English as a second language), TESOL (Teaching English to speakers of other languages), and ESL (English as a second language, a term typically used in English-speaking countries, and more often referring to the learning than the teaching). Students who are learning English as a second language are known as ELLs (English language learners).