Twi is also known as Twi-Fante and Akan. It is the main language of the African state of Ghana, mainly concentrated in the southern part of the country and west to Ivory Coast. About 40% of the population speak Twi, representing 19 million speakers. Dialects of the language include Asante, Akuapem or Twi, and Fante. They are mutually intelligible when spoken, but use different systems of writing. Since 1978, a standard writing system for Akan was established, and that is taught in the schools. This orthography contains approximately 20,000 words. Twi was exported to the Western Hemisphere in the days of slave trade. Vestiges of the language can still be found in Surinam and Jamaica.