I’ll show the easiest way how to change the language of the InDesign CC interface.
Step 1. Open Applications > Adobe InDesign CC > Presets > InDesign Shortcut Sets
Step 2. Rename the folder “en_US” (default) to cs_CZ (Czech language).
Here you can find language abbreviations.
Step 3. Restart InDesign.
If I want to change the language back I should rename the folder again.
Tip: There is a bug, workspace doesn’t look normal and there’s no option to select the workspace. To fix it Open Applications > Adobe InDesign CC > Presets > InDesign Workspaces and change the name of the folder to cz_CZ.