I wanted to use TweetDeck desktop app for Windows to post on some Twitter accounts in Serbian but when I started typing Cyrillic letters, they didn’t show up. I looked through settings (apparently not good enough) but I didn’t find any related to my problem.
Then I did some searching and found solution. Thing is that for some strange reason TweetDeck allows you to type only in Latin script. If you want to type in Cyrillic, Arabic, Japanese, Chinese or any other script, you need to go to settings, then chose Color/Fonts and under TweetDeck Font choose International Font / TwitterKey.