ESL is an acronym‏‎ for English as a Second Language.

ESL students are people learning English as a second language, that is, as another language after their mother tongue‏‎ or primary language.

ESL programs are mainly for people living in an English speaking country, for example many US citizens speak Spanish and learn English as a Second language to live and work in the USA‏‎. Likewise immigrants to a country like the UK will need to learn English to live there successfully and this will be English as a Second Language.

Teachers who teach ESL classes are defined as TESL‏‎ teachers as they Teach English as a Second Language, which is different from teaching English as a native language. To become a TESL teacher you need specific teacher qualifications.

Compare ESL to EFL‏‎ which is English as a Foreign Language. This is taught to students who are living in a non-English speaking country and wish to learn English for business or pleasure, etc.

Useful Links

Learn to Teach ESL – a course on teaching English as a Second Language

EFL‏‎ – English as a Foreign Language – all about EFL (compared to ESL)

TEFL‏‎ – Teaching English as a Foreign Language – all about TEFL

TESL‏‎ – Teaching English as a Second Language – all about TESL