The design of a software system or component starts with specifying its requirements; traditionally, use cases written in natural language are used for this task. While this makes use cases easily readable, it neither permits reasoning on requirement specifications (written as use cases), nor employing the use cases in deriving an initial design in an automated way. While employing linguistic tools to analyze use cases has already been considered, such efforts usually attempted to utilize all the information possibly contained in a use case specification, thus facing the complexity of a natural language. Yet, in a use case, the sentence describing a use case step adheres to a simple prescribed structure, and describes an action, which is either a communication action (among entities involved in the use case), or an internal action.