"Good Evening" in Twi (the principal native language of Ghana) is "Maa jo". Other sources suggest that it's "Maadwó" or "Memá mo adwó" (good evening to several people).
Twi is a dialect of Akan, a member of the Kwa sub-group of Niger-Congo languages. There are about 7 million Twi speakers, mainly in Ghana. Major dialects of Twi include Akuapim Twi, Fante Twi and Ashanti Twi, which all mutually intelligible.
For people traveling to Ghana for only a short amount of time, trying to become fluent in Twi, may be a bit farfetched. However, learning some important phrases before you go can help prepare you for a more comfortable experience.
Check out 10 important phrases to know before going to Ghana at Gadling.com.