Factory Reset MacBook but it is in Japanese
The OS Controls language. You will need to boot a different OS to that machine and run through the set up assistant to choose a different language for the new OS or you need someone to make you a new user account on that machine to change the OS. 


https://support.apple.com/en-us/HT204904


The only thing that can foil this plan is if there's a firmware password on the Mac. That would prevent you from Internet booting to recovery or bringing another external  OS to the Mac