English as a second language is English for nonnative speakers. Because it involves learning across the life span, it is sometimes considered to be a subfield of educational psychology. English for nonnative speakers is referred to by several acronyms: ESL (English as a second language), EFL (English as a foreign language), EAL (English as an additional language), and ELL (English language learning). There are also related acronyms, such as TESOL (teaching English to speakers of other languages). The history of ESL instruction and research will be covered in this entry, as will current practices and key issues in the field.