In this paper, we investigate how the interactions of a robot with its environment can be used to create concepts that are typically represented by verbs in language. Towards this end, we utilize the notion of affordances to argue that verbs typically refer to the generation of a specific type of effect rather than a specific type of action. Then, we show how a robot can form these concepts through interactions with the environment and how humans can use these concepts to ease their communication with the robots. We demonstrate that iCub, a humanoid robot, can use the concepts, which it has developed, to to understand what a human performs, perform multi-step planning for reaching a goal state as well as to specify a goal to the robot using symbolic descriptions.