My kids can swear in Russian as they play CS:GO ...
I enjoy when I get foreign language players of a language I know some of, it's a good way to practice IMO - wish one could choose a preferred language.
I guess they don't do that because of the impact on matchmaking (mm), the mm seems crazily sub-optimal I'd love to know that logic behind it : like when you have a game of 9 people, why you abandon it rather than finding a person from the pool of 100k waiting that will play. It could be a setting "allow game requests from mm" and they could give a little xp for it - beats searching and waiting another 10mins to start a game.