Have same problem - think you cannot disable it -- down to the version of the firmware loaded on the phone.
Try *#1234# To check Software and Hardware information, PDA, CSC, MODEM (Firmware Version)
On my phone I get
AP: I9305ZHBMD1
CP:I9305XXBMD2
CSC: I9305TGYBMD1
IF you look them up you will find all the elements of the code indicate the phone is programmed for Hong Kong -- not so good when its in England !
Saying that the only real problem I have had is that some accented characters come out as Chinese ! Ok not used a lot but is just a pain !
Now reading up on how to change it and hunting down the right versions of the code, but proceeding with caution, may be an Electronics Engineer with a lot of Linux experience -- but first steps in Android -- last thing I need is a bricked phone :'(
Dave