The Different Tone Systems for Tonal Languages

The more simple systems are two tone and three tone. If you go more than three, you usually have contour tones added into that which a contour is falling or rising. Once you get to tone contours, weird things start to happen. For example, Burmese has four tones, I think. Two of them use modal voice. One of them uses breathy voice. one of them uses creaky voice. And those are pretty common in Africa.