If all you want is menus in English, there are dozens of tutorials on Youtube for performing this simple change on your current box.
OTOH, the S905X box (MDZ-18-AB) just released with official AndroidTV supports many world languages, English being one of them. It is the first Xiaomi TV box designed for the international market. All earlier models are dedicated domestic Chinese market.
It would be virtually impossible to port the Mi Box official AndroidTV rom to this, or any other device.