I wouldn't buy a "used" MaxiSys Pro from China unless I lived in China, personally knew the seller as a good friend and he let  demo it for a couple weeks before giving him like $700 so I could at least have a working J-box for programming stuff off laptop if the Diagnostic software quits out of update period with no way to create a working backup software. , LOL. I assume you bought one locally that was once bought new from Mainland Chinese Dealer that you are worried about the update being in Chinese, It depends on what language it's in now
  IMO, The $1200 update price is not worth admission  unless you pretty much specialize in BMW, Mercedes, and VW, Audi and do a considerable amount of flashing to the makes. It's too bad you can't opt to update the car software for $700 as a regular MaxiSys  if you do not program BMW, Mercedes , and VW makes very often, but still could use the J-box when needed off laptop for other makes with a purchased OE sub. 

If the authorized language is English  there is no way to go back to Chinese unless you ask Autel to authorize the software back to Chinese language.