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