CALL = Computer Assisted Language Learning
EFL = English as a Foreign Language (Studying English in non-English-speaking countries)
ELT = English Language Teaching (or sometimes Training)
ESL = English as a Second Language (Studying English as a non-native speaker in a country where English is spoken. Depending on where you are from, the term ESL may be more inclusive and includes EFL. For some people the reverse seems to be true.)
ESOL = English to Speakers of Other Languages (Note: ESL and EFL are often used interchangeably. This acronym is an attempt to make a generic term and then assign more limited meanings to ESL and EFL.)
L1 = "Language 1" = the student's native (primary or first acquired) language.
L2 = "Language 2" = the language being learned or studied
TEFL = Teaching English as a Foreign Language
TESL = Teaching English as a Second Language
TESOL = Teaching English to Speakers of Other Languages (It is also the name of an association, Teachers of English to Speakers of Other Languages, Inc.)
TOEFL = Test of English as a Foreign Language
TOEIC = Test of English for International Communication
CREDIT TO http://iteslj.org/. Care to visit the website.