2.attempts to attract learners attention to forms in the course of instruction that is not explicitly designed to teach them and thereby to cater to incidental acquisition. Long (1988, 1991)
Focus on form is defined by Long (1991) as follows: 1.Focus-on-form refers to pedagogic, not to mental activity. Thus it takes place interactionally and involves observable behaviour. 2.Assumption is that teacher and learners are both primarily focused on using language communicatively, not with trying to learn the language.
3.Despite this focus-on-meaning, occasions arise when the participants need to or choose to focus on form. 4.A final assumption is that focus-on form is necessarily occasional and transitory, as otherwise it would supplant the primary focus-on-meaning.
Thus focus-on-form to can be seen as involving these criterial features; 1. it is observable (i.e. occurs interactionally), 2. it arises incidentally, 3. it occurs in discourse that is primarily meaning-centred and 4. it is transitory.
Each of these two types of focus-on-form can be realized by means of a number of discoursal strategies. For example, reactive focus-on-form can be conversational or didactic. Conversational focus-on-form occurs when the attention to form arises in the course of dealing with a communication problem resulting in the negotiation of meaning as in example 1 below.
Much of what goes on in the name of language teaching is directed at intentional learning through focus-on-forms instruction. Linguistic items or language skills are are explained to students and then practised with a view to automatizing them. Students know what it is they are supposed to be learning and are invited to learn them intentionally. There is no doubt that in a classroom context, intentional language learning is both natural and desirable, especially for older learners.