Something that Android Wear 1.x was sorely missing was support for on-screen keyboards. It just isn't ideal in some circumstances to have to talk to your watch. Naturally, one of the features people got most excited for in Wear 2.0 was the ability to type using a keyboard. However, it appears that some languages' keyboards have some missing characters.
There are two reports of this happening on the Google Product Forums' Android Wear Help Forum: one with the Russian keyboard, and one with the Hungarian keyboard. Both situations involve watches with circular screens (LG Watch Urbane and Huawei Watch). For the Russian keyboard, the 'Х' 'Ъ' 'Э,' and 'Ё' characters are missing. It's unclear what the Hungarian keyboard is missing due to a borked screenshot.
top: Android Wear 2.0 keyboard. bottom: standard Russian keyboard.
As a forum user did note in a comment, two of the characters can be substituted by long-pressing other characters ('Ё' for 'E' and 'Ъ' for 'Ь'), but that still leaves 'Э' and 'X' out. From what we can tell, this seems to be due to the round screen cutting characters off. Though both of these issues are from a few months ago (April and May), both have just been replied to by a Google community manager with this message:
"Hi,Just wanted to update this thread to say that this has carefully been considered and will be coming in a future update.Thanks everyone for your feedback!"
In other words, Russian and Hungarian speakers won't have to live without some necessary characters on their Android Wear device's keyboards for too much longer. It's entirely possible that other languages are affected as well. Quite honestly, this is pretty hilarious not just because nobody noticed this in development, but also because it took months to resolve. Google isn't doing their "treating customers like beta testers" reputation any favors.