Default [Q] Galaxy Note 3 change language on its own?

Hi, I am newby so to come down on me if this is a dumb question

I have a quite new Galaxy Note 3, which today, whilst sitting in my pocket untouched, managed to change language settings - apparently independently - to an asian language; so that when I reached for it next, everything was coming up in an asian character set. It even managed to change my Samsung Gear in the process. I can't think why this has occurred. The only unusual thing that I have done recently is load Google Now, using the instructions and links found on this website.

I have managed to get the language back to english using some online searching to work out which buttons to press in settings... but I am wondering if there is something I need to do to avoid this happening again, or whether there is something more serious happening in the background.

Could it be that the Google Now (which incidentally works except the voice command "ok google" does not work) had some bug or issue in it, or has opened up a vulnerability?

Incidentally my Gear has seemed a little buggy as well since installing Google Now (e.g. messages not coming through straight away, or pressing on the message notification does not open the text but rather a menu) - in fact I had to re-sync after installation.

Also, before the language change, a little earlier on, the phone suddenly disconnected bluetooth devices, in this case cutting off my car's handsfree in the course of a call (as well as my Gear). This has never happened to me before.

Any advice appreciated... Thanks in advance!