Task based language learning

Task based language learning by Dave Willis and Willis.

Task based learning ( TBL) involves the specification not of a sequence of language items , but of sequence of communicative tasks to be carried out in the target language.
J.Willis (1996) defines a task as an activity ' Where the target language is used by the learner for a communicative purpose (goal) in a communicative task is seen as bringing about an outcome through the exchange of meanings.
One obvious outcome is the exchange of information in spoken or written form.
One feature of TBL , therefore, is that learners carrying out a task are free to use any language they can to achieve the outcome: language forms are not prescribed in advance. As language users , human beings have an innate capacity to work out ways  of expressing meanings. Learners do not simply take note of new language input and attempt to reproduce it.
Skehan (1992) suggests that learning is prompted by the need to communicate , but argues that learning will be more efficient if :
1) There is a need to focus on accuracy within a task based methodology.
2) There is a critical focus on language form within the task based cycle.
TBL like CLT rests on broad principles rather than precise recommendations or prescriptions.
The need for a focus on form within a task based methodology may be met in part by manipulating the circumstance of communication in the classroom.