I learnt english by reading books. That might help, although reading can be quite a passive activity, so you might want to couple it with some writing activities to make sure you’re actually doing something so it sticks better. I’m also not sure how well that will work for your specific problem of struggling with conversations, but tbh I’m not great at speaking to people irl myself (although that applies in my first two languages—english is my third—as well so I don’t think it’s a language barrier thing so much as my brain thing) so I dunno what would help with that specifically.