Fiio R7 Manual page 40

Languages & input
The first time the device starts up, you can choose an appropriate language
from the prompt.
If you want to choose other languages, you can go to the Settings menu. Here
are the instructions.
1) Go to the menu of Settings-> System-> Languages & input-> Languages;
2) In the Languages page, tap Add a language;
3) Select a language;
4) After selecting the language, hold the "=" icon on the right side of the target
language and drag it to the top, so to successfully select the language.