Specifics
In order to support the machine translation service, a mobile device needs to be able to communicate with external computers (servers) that receive the user-input text/speech, translate it and send it back to the user. This is usually done via an Internet connection (WAP, GPRS, EDGE, UMTS, Wi-Fi) but some earlier applications used SMS to communicate with the translation server.
Mobile translation is not to be confused for the user-editable (talking) dictionaries and phrase books that are already widespread and available for many hand-held devices and do not normally require internet connectivity on the mobile device.
Read more about this topic: Mobile Translation