It is believed students should develop their communicative ...

It is believed students should develop their communicative competence since the main aim of learning a foreign language is to communicate in an effective way. In order to do so, teachers play a pivotal role when planning and delivering their lessons which are expected to develop students’ competences in the language. 

What are the four main elements of the communicative competence framework presented by Canale and Swain (1980) which is the foundation of many studies on English language teaching like Almeida Filho (2005)?