Why are the five skills useful?
In-order to become a well-rounded communicator one needs to be proficient in each of the five language skills. These skills give learners opportunities to create contexts in which to use the language for exchange of real information, evidence of their own ability (proof of learning) and, most important, confidence.
Listening and reading are the receptive skills because learners do not need to produce language, they receive and understand it. These skills are sometimes known as passive skills. The productive skills are grammar, speaking and writing because learners are applying these skills in a need to produce language. They are also known as active skills.