So outside of Camtasia, go to your System Preferences... (under the 'apple' menu) and choose the Language & Region tab. If English isn't in the list of Preferred Languages, choose the + button below the list to add English. Once English is in the list of Preferred Languages, click and drag it in the list so it is above other languages (at least above German or French if they are in your list). Don't drag it to the very top unless you want English as the primary language for all applications and the OS on your system. If Camtasia was already running, you'll need to close and restart it. It should now be in English instead of German (or French).