ESL means English as a Second Language: the teaching of English to people who are living in an English-speaking country but whose first language is not English. A child who moves to the United States or Britain and then learns English at school is in that kind of class.

ESL meansESL 的意思是 English as a Second LanguageEnglish as a Second Language（英語作為第二語言）：the teaching of English指教英語 to people who are living in an English-speaking country給住在英語系國家、but whose first language is not English但母語不是英語的人。A child who moves to the United States or Britain一個搬到美國或英國的孩子，and then learns English at school然後在學校學英語，is in that kind of class上的就是這種課。

Though actually, the letters get used loosely. US schools say ESL a lot; Britain often says ESOL or EAL instead, and some places now say EL or ELL, “English learner.” This is the bit Taiwan students mix up: if you learn English in Taiwan, you are usually doing EFL — English as a Foreign Language — because English is not the language of the street here.

Though actually不過其實，the letters get used loosely這幾個字母用得很鬆散。US schools say ESL a lot美國學校很常說 ESL；Britain often says ESOL or EAL instead英國則常改說 ESOL 或 EAL，and some places now say EL or ELL, "English learner"有些地方現在說 EL 或 ELL，也就是「English learner」。This is the bit Taiwan students mix up這正是台灣學生會搞混的地方：if you learn English in Taiwan如果你是在台灣學英語，you are usually doing EFL你通常做的是 EFL——English as a Foreign LanguageEnglish as a Foreign Language（英語作為外語）——because English is not the language of the street here因為英語不是這裡街上的語言。

ESL is for when English is all around you outside class. The two overlap in real life, and some teachers just say “English teaching” to avoid the fight.

ESL is forESL 是給 when English is all around you outside class課堂外、英語就在你四周的情況用的。The two overlap in real life這兩者在現實生活裡其實會重疊，and some teachers just say "English teaching"有些老師乾脆就說「English teaching」，to avoid the fight省得爭這個。

ESL is a normal school and university word, not slang.

ESL isESL 是 a normal school and university word學校和大學裡的正常用詞，not slang不是俚語。