Jeremiah, 
“You will never understand the culture unless you speak the culture’s language fluently,” is such a bizarre argument to make to an immigrant.
Why would you refuse to share your culture with me because of a language barrier?
How much of a loss for me is it really if you refuse to share your culture because I don’t speak your language?
Some of my best understandings of other cultures have come from food and behaviors. And mean comments to me on social media in my native language.