I was just adding some observations to a project, and I accidentally tried to add some that I already had. iNat gave me a popup with a list of observations that couldn’t be added to the project, and the common names were in a different language (I think french).
My locale is set to “English (United states)”, and I don’t have a place set to prioritize common names from. I have scientific names set to show first, so maybe that has something to do with it?