1) Alien subj 2) Au pair class 3) Bilingual subj 4) Bilingualism subj 5) Certain adult education class 6) Certain language course 7) Class for future US citizens 8) Class for immigrants 9) Class for many US immigrants 10) Class for new US arrivals 11) Class for new US citizens 12) Class for new US immigrants Found on https://www.crosswordclues.com/clue/esl
English as a second language: the study of English by nonnative speakers in an English-speaking environment. Cf. EFL. Found on https://www.infoplease.com/dictionary/esl