If you could totally immerse yourself into a foreign language - where it's all you hear, read and speak - it teaches you to think in that language rather than mentally translate it into your native tongue. So when you hear "casa" you don't think the word "house" you just understand it as a house. I always thought that would be cool to be that fluent.
When I visited Portugal, I thought Portuguese was the hardest language I had ever heard. I may not speak much French, but I know when someone is speaking French when I hear it. The same with Italian or German, but I had no idea what language I was hearing the first time I heard someone speaking Portuguese. It has many words similar to Spanish but it includes German-sounding words and even a touch of Japanese! They claim it was because they had been conquered so many times by so many different nations. I did learn some of the basics like "good morning", "where is the bathroom" and "two cold beers, please". :o)
“If you could totally immerse yourself into a foreign language - where it’s all you hear, read and speak - it teaches you to think in that language rather than mentally translate it into your native tongue. “
Chomsky, even though he is a commie, has lots of good ideas on language acquisition, at least for a child’s first language. Nevertheless, I think his ideas on Universal Grammar (that there is an innate language learning ‘store of knowledge’ in the brain, separate from the other processes of the mind), which is activated through immersion, can teach you a lot about how to acquire another language. Learning and acquiring are two different things by the way, and it is that “acquisition” which you are speaking of when you mention understanding “casa’ for what it is, without having to translate it into your first language.
People can go many years studying the grammar of a language, and they may “learn it,” but they’ll never acquire it until they actively use it in social interactions.
That is the way I am learning ASL, from a deaf teacher that refuses to even let us speak in class. everything is either ASL, pantomime, or drawing.