I’m from Vietnam. I’ve been in the UK for 10 years now. When I met my English husband 13 years ago at 19 I knew 0 English. We communicated using machine translation. So that’s when I started learning English. Fast forward to present day after immersion, living in an English speaking country, formal study, etc. and I’d say my writing and listening (understanding) are good, but my speaking and reading are still bad. I kind of gave up on trying to become fluent at this point.
I talk about how grown-up people study a foreign language.
Most adults I know who study a foreign language do so in order to speak it, perhaps visit that country. In languages that build words from letters, the phonemes are important to meaning. Obviously “heresy” is very different from “hearsay,” but sow and sow are different words that sound different, while sew and so are also different but sound the same. It’s especially important in order to appreciate literature, poetry, music, and jokes.