If you have a Meizu device released in 2016 VoLTE may work directly or with some tinkering with the engineer mode. Yes it supports English language and that's the only language it supports except for Chinese. 3 stable firmwares have been released for the A firmwares depending on your device the number can vary. And another stable will be released this month. If the version number of the Chinese firmware for your phone contains Y in it then do note that it won't support Google services and it also cannot be rooted. However, if it's A then you're good to go.