n 73 is nokia series 60 os 9.1 fone. if u seriously mean to have translate phone options completely in gujarati language like currently we have in some english and malay and philopino ,, then its not possible unless we FLASH it and put gujarati language pack in to it . but i am doubtfull if any indian language pack available from nokia.
if u happy with just reading gujarathi sms and writing gujarathi sms like in unicode script ( like T in TamaaTar and t in talwaar ,, d in deewaar and D in Damaroo etc) then u need following software
hope u happy with this