Twi

Twi, also known as Akan or Asante, is one of the Kwa group of Niger-Congo Languages. It was the language of the Ashanti empire, which dominated a large portion of Northwestern Africa in the 19th century, and is now the most widely spoken native language of Ghana, with about 7 million speakers.. As the language of the priesthood and of liturgical texts in the Ashanti religion, still widely practised in Ghana, Twi is important to many non-native speakers as well. There are three standard forms of Twi , all mutually intelligible: Twi or Asante (of the region of Kumasi, center of the Ashanti empire), Fante and Akuapem (of southern Ghana).
Twi has two tones - high and low. It also has a 'vowel harmony' rule based on the position of the root of the tongue: a word may contain either advanced or unadvanced' vowels but not both. In the Fante dialect, vowel harmony is more complex.

Sources:

Worldlanguage.com
Background to Ashanti
Britannica.com
Ethnologue

Independent Study Courses Available at UCSD:

• Conversational Twi, LIDS 19
    Redden, Twi Basic Course (Tape)

Other Local Resources:

UCSD International Center
Mingei museum of folk art