based on localized version of firmware you can choose from abt 4 languages via phone menu. If your wanted language is not in the offer than phone is not from your region and you have to ask e/// service point to flash your phone with new flash for your region.
hi .. there is an special sw and also special hw to do it .. it is quite difficult and takes long .. abt 15-20 mins. I would say that you need e/// service sw ..
The software and hardware to flash new code into a cell phone is closely guarded by all cell phone manufacturers. It would be very difficult to get this.