Understanding acceleration

I don't understand, which is angular acceleration and which is linear acceleration?

Acceleration of radius = ?
Acceleration of tangential = ?

tangential acceleration is how much your velocity is increasing in a straight line tangent to a point on the circle. it is what your acceleration would be if it suddenly started going straight.

angular acceleration is how much the angular velocity changes. When you have a particle moving in a circle, it's number of degrees/radians is constantly changing, the rate at which the angle changes for the particle is the angular velocity, and the rate at which the angular velocity changes is the angular acceleration.

Tangential acceleration is linear acceleration. Radial is angular.