Open the Language & Region control panel in System Preferences and make English your primary language.
You don't need to restart the system or close the Preferences.
Now run Fontlab Studio and activate it. After you have activated Fontlab Studio, you can switch back to your preferred language.
Fontlab Studio makes its choice of which language to display the interface in based on your system preferences.
There is a workaround to force FontLab to work in a different language regardless of your language preferences:
Open the application package, and delete the folders for the languages that are higher in your prefs list than the one you want FontLab to use. The folders have names such as “Spanish.lproj”.