In language teaching, it is important to initiate individuals into intentional activity whilst understanding the need to develop structural competency. The following discussion is influenced by a usage-based approach to language acquisition.
It so follows that the individual develops language in an intricate give-and-take navigation with other language users in the pursuit of shared intention and joint construction. As a consequence, a user's repertoire of language practices is directly correlated to the user's participation in the collective intentional activities of a community of practice, which includes both verbal and non-verbal activities in the pursuit of socialisation.
A critic of the above approach would be correct to point out how children produce quite immature utterances, even though they may be surrounded by rich language experiences. It is true to note how novice users must endure early stages where it is a challenge to gain mastery of manipulating the structural and formal elements of the linguistic symbolism before being able to speak, listen, read and write with confidence.
Whilst mastery of structural elements is highly relevant in language teaching and learning, we must acknowledge that language acquisition is reinforced in the collective intentional practices, habits, relationships and spaces where language events occur.
We should be concerned with developing linguistic competence within goal-oriented learning or in manners contingent with the practices into which a novice is being introduced. And since the novice is being introduced into new activities which may lie outside existing competencies, it is important that more experienced members of that community arrange activities in such a way that learners can develop gradually and thoroughly. We desire that new learners are able to develop structural fluency and internalise practices into their modus operand.
We are interested in how discourse practices arise and how new users come to participate in adapting to the phrasing, structures, choices, context and purposes of the skills. Structural mastery is insufficient for an individual to incorporate the range of practices necessary to be able to be impacted and to impact in given spheres of activities.
"People have not had the same opportunity to learn unless they have had equivalent experiences within the relevant semiotic domain in terms of active and critical learning. Further, they must have had equivalent experiences with the range of non-verbal meaning resources in a domain and how they relate to words (since these other resources are often relevant to what words mean in the domain)." (Gee, 2003, pg 33)
There is no essential "language skill" in a usage-based approach. In a usage-based approach, one is constantly aware of the continual development of new language constructions, vocabularies and codes. A usage-based approach also reinforces that one can fall out of certain practices, whilst still retaining other practices (or else we would forget the role of the phrase "I once knew" or "I knew at one stage").
We hope that one can speak and can understanding a particular lingo when initiated as part of a community of language practitioners. When one leaves that community, the instinct or intention to use language in such-and-such a way may recede or lose currency in one's set of linguistic practices.
References
Gee, J. P. (2003). Opportunity to learn: a language-based perspective on assessment. In Assessment in Education: Principles, Policy and Practice, Vol 10, No. 1, pp 27 - 46