If you find that all of Don't Starve's text/fonts suddenly change from Simplified Chinese to question marks (????) this is likely due to the game's option "Small Textures" being enabled, causing the issue. (Chinese language translations do not support the "Small Textures" option at this time.)
The best way to resolve this is to launch the game and when you get to the game's main menu screen, open up the game's Console Command line by pressing your Tab (~) key.
On the console command line, copy & paste the code below and press your Enter key:
TheFrontEnd:GetGraphicsOptions():SetSmallTexturesMode(false);SimReset()
This will disable the Small Textures option for the game, and allow the game to show the Chinese language translations properly.