How to Change NotePlan's Language
NotePlan is currently available in German and English versions. If you want to switch between them and do not have either as your system language, you can do so via your Mac's settings.
If you go into your Mac's System Settings under "Language and Region" there is a setting where you can change the language for an individual application.
From there, you should be able to change NotePlan's language to English from German or vice versa.