It’s interesting you say ‘But I know foreigners who are understanding literally everything in french but prefer to communicate in english. ‘
I know most learners hate the way they sound in a different language, they don’t like the sound of their own voice in a foreign language. I guess listening helps but if you can’t pronounce the word, you need practice.
Also it must get frustrating at some point to understand but always reply back in your native language. I think it more tiring!!!!