I met a guy that came over from Russia when he was a teen. He had NO Russian accent - it was hard to believe. I asked him how he learned to speak English so well.
“I watched a lot of cartoons when I first came over.”
When I was a kid, one of my best friends was from Taiwan. He learned to speak English by watching American cartoons. The only hard part was he talked like a cartoon character, which got him some ridiculing by other kids. For example, he thought the plural of mouse was “meeses.” Or he would say something like “I eats my spinach (substitute other food here).”