As I understand it, "walk" is the smoothnes (or lack of) that the blade opens with as it moves along the backspring, and "talk" is the force that the blade closes with (snap). Basically you are looking for a smooth operner with a nice positve snap when closing. Both walk and talk are directly related to the quiality/design of the back spring, although a pivot that is sloppy or too loose would change the mix some.
michael