I think this is important for the whole community and there are only benefits.
I also understand the struggle of some people when using English but when you leave to someone feedback it's to inform the rest of the members. At least a rule for those who are on DT, if you end up there you need to take the responsibilities as well.
Simple example of a DT feedback >

While I understand your issue, this could have some negative monoculture type results. IMO if you don't speak the language of your trading partner you should probably in general not be trading with them anyway.