That’s a good one, and plenty frustrating I’m sure.
If it was never touched, I’d assume the unit was still set to the Language selection setting, but my thought is that all kinds of buttons have been pressed trying to get the unit set back to English.
Since you can’t read the language in the display or menus, it’s hard to say how to give you step-by-step directions to get you back to where you change the language, as those directions will be based on what function the unit is set to now.
Can you determine which function the unit is set to, such as “Play Music” or to the radio, etc., or do you know if there’s been any change in the settings since the language was changed?
If you can determine where it is, I’m sure some of us on the forum can give you some instructions like, “Press “Menu” button, press the “down” button three times, press “Select,” etc…”
I’m no expert, but I’m not aware of any global “Reset” button or anything like that on the unit.
Worst case, if we can’t help you, and if you’re sure the unit’s been set to Chinese, you might be able to appeal to someone to help you from the Foreign Language department at a nearby college or University, or someone at a local community/cultural center that supports the Chinese culture.
You might also want to change the title/subject of your post to be a little more specific. You might get lucky and find someone on the forum who can read the language and help you navigate your way back.