I understand your situation. But what I meant to say by "immersion" is to not speak or listen to your native language, just the language that you want to learn for long periods of time. In my teenage years in NY I started learning to communicate in English at my workplaces (part time jobs) because I had no choice. At the beginning my brain was engaged in language translation, so the process was quite slow, but slowly things started falling into place, and eventually I even dreamed in English

. About ten-fifteen years later I enlisted in the military, and again I could only communicate in English. In my last years of service I was already translating documents. The most difficult for me was pronunciation.
Just imagine landing in an isolated island where your language isn't spoken. That's the kind of immersion I was referring to. Nowadays one can take crash courses to learn the most common (street talk) of most languages. This is done in the military, too.
Now, about your HS Spanish classes: In Spanish, just like english, there are ways to say the same thing with a few words. It may not be grammatically correct, but you still can communicate while omitting a few words. You can see this when your have a group of Italians, Spanish, and English speaking friend or neighbors talking to each other. A lot of the words are omitted.