So today a new post has been posted on Steam
saying a Czech and Japanese voiceovers has been added.
Are they already added in the GOG version as well?
I noticed GOG Galaxy pulled & installed a huge update (over 17 GB) for KC:D for me today, the patch release notes didn't show anything specific though. The patch is marked 1.9.6-404-504czj3 so I suspected the CZ voice files might be included - and bingo, it works like a charm. After launching the game I have CZ as an option for both the voice/sound and the texts & subtitles now. Tested in game for about 15 minutes, all seems to be working well.
A nice surprise that we finally got it after years of waiting ;)
Perfect, thanks for confirming this.