If HabitGuru displays in an unwanted language then please check your installed languages.
Maybe you have a language installed you don't actually want.
HabitGuru automatically chooses a display language according to your settings and defaults to English if no supported language is found.
Please go to your phone's settings, then choose "System".
Here you should find "Languages & input".
Below that there should be "Languages".
Please check if you have a language installed that you don't want, e.g. German or Arabic.
If so, then open the menu by clicking on the three dots in the top right corner.
Now tick the languages you want to remove and then press the trash can icon.
After confirming your choice, the unwanted languages should be installed and HabitGuru should be displayed in one of your chosen languages, or in English.