In Ghana, the official language is English, but many people in underdeveloped cities or towns do not speak English. But they speak a language called Tri for central regions, or in western regions they speak Fanti. And they're very, very similar languages. Learn as much Tri as you can, but remember the official language is English, so you want to start with that.
So the thing that helped me the most when I was learning was I just started learning all the pronouns. So when I started saying a bunch of words really rapidly, because everything sounds like it's actually one word, though it's a full sentence, I was able to pick out who they're referring to, and then I was able to insinuate what the verbs were. So if I want to say me, I'm going to say me. If I want to say you, I'll say wo. If I want to do plural you, like a group of you guys, I'll say mo. And if I want to say him or her or they, you'll say o. Okay, so we got the wo, mo, o, and me. It's going to sound like one word. Things like I'm coming, merhaba. Things like I'm eating, medidi. Things like I'm hungry, akamadimi. You got to kind of pick apart each word so that you can begin to understand and recognize that it's going to sound like just a waterfall of words, but each one can really be broken down into a lot.
Practice failure. When you hear someone say something, say it again and allow the guineans to make fun of you because it's only going to help you to learn and grasp the language. So say it, say different words that you learn and allow them to correct you because it's only going to help you to be able to pronunciate the words properly.
Fun language facts about Ghana. For the most part, Ghana has 23 languages. They're all dialects of Akan. You're going to run into Fanti, Chi, Nzima, Ewe, probably Frafra and Igbo. The only ones I would expect you to learn is Fanti and Chi. You probably won't learn them fluently, but you'll learn them enough to understand people and buy things and just general communication. The more you speak, the more the people will love you.