According to the documentation Introduction to Localization on Roblox you should be able to change what language to test the game with in Studio.
Steps to reproduce:
- Open Plugins → Localization Tools Window
Expected results: The Localization Tools Window should contain a dropdown to select available test languages
Actual results: The Localization Tools Window does not contain any option to select test language
Impact: It is not possible to test localizations in Studio
I have looked around in Studio if the test language option has been moved, but only found where you can set the Studio interface to Chinese.