For
It may make them feel excluded.
Against
People should be free to speak their own language.
Anonymous excerpts, translated where noted.
“It's kind of the bare minimum expected from people to be able to communicate as a team.”
“I find it rude and annoying, irl and in game.”
“It shouldn't be considered rude to speak in a language that folks around you don't understand.”
“I am free to speak any language anywhere I want.”