SRS is the most potent ways to build your vocabulary when learning foreign languages and is in fact a great way to learn just about anything. SRS is essentially an optimised way or revising lists of information, or in the case of language, revising vocabulary lists. With SRS each time you revise a word and remember it’s meaning, the time to the next revision of that word is increased; conversely where you get a word wrong the time to the next revision of that word is decreased. The result of this is that you revise words you know less and less often. SRS doesn’t have to be used for language lists, it can be used for revising any information that is suitable for memorising with flash cards.