Twi is spoken in the southern two thirds of Ghana, mainly between the Volta and Tano rivers, but in the last few centuries it has spread over a larger area, especially to the west, so that there are now a large number of speakers in contiguous areas. There are about three million native speakers of Twi, plus about one million more persons who regularly use the language. All dialects of Twi are mutually intellegible; but at conversational speed and on some subjects, speakers from distant areas may have difficulty understanding one another.