Thanks for mentioning literacy. Most of the other suggestions, both in the original post and in other threads, focus on speaking and listening skills. While tho

Thanks for mentioning literacy. Most of the other suggestions, both in the original post and in other threads, focus on speaking and listening skills. While those are important, they're only part of what you need if you want to use a language at a high level. A Russian teacher I had in college more than forty years ago told us about her experience. As a teenager, before World War II, she had moved with her family to Austria. When they arrived, she understood no German whatsoever. The way she learned it, she said, was just to read book after book in German. While she didn't understand what she read at all when she started, within a few months she was, she said, fluent, thanks mainly to the extensive reading. Systematic study in school and social immersion no doubt helped her as well. I had been studying Russian for several years at that point and had reached a plateau, frustrated at being unable to read literature without looking up most words in a dictionary, so I tried what she suggested. Over the next couple of years, I read my way through dozens of novels and nonfiction books without using a dictionary. While I understood very little at first, the repeated exposure to vocabulary and grammatical patterns in meaningful contexts kickstarted my acquisition of the language, and soon I was enjoying Tolstoy, Chekhov, and the like in the original. In my case as well, continuing to study vocabulary and grammar systematically, both in class and on my own, also helped. I applied the same technique when I moved to Japan in 1983. After having learned hiragana, katakana, and a few hundred kanji, I started reading real-world texts—newspapers, magazines, novels—straight through. I understood very little at first, but I made steady progress and after a couple of years I was able to start working as a Japanese-to-English translator. Once again, the effect of the extensive reading was boosted significantly by continuing to take language classes and to memorize vocabulary. The immersion in Japanese society also helped, of course. I'm really glad I made that effort when I was young to learn not only to speak Japanese but to read and write it as well. That has made all the difference in my life since.