For someone trying to learn a language that is not related to their native language (let's say for example, an English speaker trying to achieve a roughly native level in Arabic), how would you go about tackling the issue of memorization of vocabulary, that is so vast and completely different?
I'm especially asking this in the context of a very high end goal, with "roughly native level" meaning perhaps 15'000 to 20'000 individual words to memorize.
I like to use spaced repetition apps, like Anki, and I mostly use cards with sentences or parts of sentences to demonstrate how a certain word is applied in the language. However, if you add, say, 20 new sentences a day, and you're in the 5 digit range already, simply trying to "hammer in" more and more of it only works to a certain degree.
So, in short, I guess my question is: What tricks or techniques are there to learn vast amounts of vocabulary in a completely different / unrelated language?