Sure, but do they know when they're saying something awkward? Recently I struggled in both England and Barcelona to get carbonated water. In San Francisco I'd be saying "soda water". In New York, "seltzer water". In England, apparently, sparkling water is the trick. I'm a native English speaker so it was fairly easy for me to pick up on that.
Meanwhile my Spanish is not great, but enough to sound like I speak Spanish fluently and make casual conversation and order things at a bar. In Havana I learned "agua sin gas" and "agua gaseosa". I tried that a few times in Barcelona (a city you can navigate entirely in English) recently and eventually got a weird look. Next time I asked and was told "agua con gas". Were it not for the weird looks I'd've stuck with awkward phrasing.
I generally tiptoe pretty gently with non-native English speakers, but have one friend who is insistent upon having their mistakes and awkward phrasing corrected. They're also the one friend who seems most like a native English speaker with written communication (the accent is a whole other story).
If you don't know when you're doing something awkwardly you won't ever improve.
My friend, randomly, said that I speak non-idiomatically / kinda awkwardly in general.
Great. What am I supposed to do with this information? I already know that. It's just frustrating, especially since at the time I was in a rut about my progress.
Telling someone who speaks a language at an intermediate level that they don't always speak idiomatically is pointless - they already know that.