*The language they spoke in Ancient Ghana was the language Soninke
About Soninke Language
Soninke (also called Marka, Maraka, Sarakole, Sarakule, Sarawule, Serahuli, Silabe, Toubakai, Wakore, Gadyaga, Aswanik, Diawara) is a Mande language of the Niger-Congo language family. It is the national language of Mali. Soninke is also spoken in Côte d'Ivoire, Gambia, Guinea, Guinea-Bissau, Mauritania, and Senegal.
There are more than one million Soninke speakers worldwide.
Soninke dialects include Azer (Adjer, Aser), Kinbakka, and Xenqenna.
It is also believed that ancient ghana might have spoken some kwa languages which belongs to the niger congo family