For me deactivating the shortcut for switching between layouts works, as my main problem was that I accidentially hit it when sprinting and crouching on SHIFT and CTRL. I still haven't found a way to stop the game from adding another language to the system. I hope you can find a solution to your problem. I am looking forward to read about your solution.
Issue still isn't fixed, so I'm putting this here for anyone who looks for this to hopefully speed up any searching you do.
This is (as far as I can tell) a really old issue with keyboard translation in the source engine, reported as far back as 2010 (wayback machine of a forum link from a steam discussions page). There is a fix for this where you edit registry files but I haven't tried it because it doesn't matter that much to me. I hope this gets patched someday but I can't really imagine it happening because Valve apparently hasn't fixed this even in CS2.
Here's the link to the steam discussion page https://steamcommunity.com/groups/SteamClientBeta/discussions/1/864976115478357063/
Community ManagerClosing thread to avoid necroposting.
