I don't know about those particular aspects of MKV, but from the article below, it appears that it is going to take some configuring to get them to play at all:
Wow thanks a lot for the response I really appreciate it, it seems that Windows 7 doesn't support MKV files yet or ever so its still a work in progress there are solutions from the link you gave me but some side affects in doing so might make you have to reload your copy of W7 so, I'll just wait till there is a safe and proper way, but thanks it helped alot.
Thanks for the help but unfortunately, I needed help on the Windows Media Center, so I can stream a MKV file to my t.v. with changed audio language and subtitles that show up on WMC while watching on my t.v.
You just drag the file over and then uncheck the boxes that you don't want to be played on the MCE. I use this for all my movies that have subtitles in them, I am still looking for a way to turn them off and on with my remote from the couch in windows 7 MCE.