CrossOver will automatically display its user interface in the same language as the macOS, but you can also specifically set CrossOver to use a different language as well. The following steps will show you how to change the CrossOver user interface language.

1. Go to the Apple menu > System Preferences.
   
2. Select the General preference and then Language & Region.
   
3. Scroll down to the Applications section and click the + button.
   
4. Select CrossOver from the list of applications if it's not already selected.
   
5. And then change the Language menu to what you prefer.
   
6. Once you click Add you will be prompted to relaunch CrossOver if it's currently running.
   
7. CrossOver will now reopen in the specified language. Repeat the steps if you want to change CrossOver back to the macOS default.