For teachers and learners of a foreign languages,learning situations may be classified roughly into two distinct types:S

For teachers and learners of a foreign languages,learning situations may be classified roughly into two distinct types:SL and FL.SL refers to that of those abroad in which the language to be learned is the local native language,for instance ,to learn English in Britain or America,or,to learn Japanese in Japan.
这段话中 SL 代表的是哪两个单词,
请翻译这段话 以及单词缩写代表什么