Grammaticalization requires specific contexts to take place, and it can be, and has been, described as a product of context-induced reinterpretation. Accordingly, context is a crucial factor in shaping the structure of grammatical forms - to the extent that they may express meanings that cannot immediately be derived from their respective source forms. (Heine, and Kuteva 2)
Grammaticalization as Epiphenominon:
Anderson and Lightfoot, further develop the concept of grammaticalization as an epiphenomenon when they discuss the essential nature of grammars, rather than the entire language concept.
From the perspective sketched here, our focus is on grammars, not on the properties of a particular language or even of general properties of many or all languages. A language (in the sense of a collection of things people within a given speech community can say and understand) is on this view an epiphenomenon, a derivative concept, the output of certain people's grammars (perhaps modified by other mental processes). A grammar is of clearer status: the finite system that characterizes an individual's linguistic capacity and that is represented in the individual's mind/brain, the language organ. No doubt the grammars of two individuals whom we regard as speakers of the same language will have much in common, but there is no reason to worry about defining "much in common, " or about specifying precise conditions under which the outputs of two grammars could be said to constitute one language. Just as it is unimportant for most workin molecular biology whether two creatures are members of the same species (as emphasized, for example, by Dawkins 1976), so too the notion of a language is not likely to have much importance if our biological perspective is taken and if we explore individual language organs,
Anderson, and Lightfoot 40)
Language as a biological process is derivative of other ideas, but is not exclusively unique in any given individuals who, generally communicate within the same language.
In that way, the emergence of a grammar in an individual child is sensitive to the initial conditions, to the details of the child's experience. So language change is chaotic, in a technical sense, in the same way that weather patterns are chaotic. The historian's explanations are based on available acquisition theories, and in some cases our explanations are quite tight and satisfying. Structural changes are interesting precisely because they have local causes. Identifying structural changes and the conditions under which they took place informs us about the conditions of language acquisition; we have indeed learned things about properties of UG and about the nature of acquisition by the careful examination of diachronic changes. Under this synchronic approach to change, there are no principles of history; history is an epiphenomenon and time is immaterial.
Anderson, and Lightfoot 185)
Further the idea that grammaticalization of a whole language and also of the individual's language reflects the epiphenomena of the functional aspects of the mind as the language organ. Anderson and Lightfoot stress that there is a great deal more than simple issues of the utilization or change of the utilization of grammatical laws that determines the foundational changes that occur within language and the individual learning language, and therefore such changes are dependant upon other phenomena, i.e. epiphenomenon.
There is more to language change, a phenomenon of social groups, than just grammar change, a phenomenon of individuals. Grammar change is nonetheless a central aspect of language change, and it is (naturally enough) intimately related to other aspects of language change. The explanatory model is essentially synchronic and there will be a local cause for the emergence of any new grammar: namely, a different set of primary linguistic data. Time plays no role and there are no principles which hold of history.
Anderson, and Lightfoot 162)
Though there are many who would argue the grammaticalization and even language itself must be studied in the diachronic rather than the synchronic, as is suggested by Andersen and Lightfoot in the close of the last statement and yet, it makes little sense to discuss the changes of language individually without seeing language through the whole and therefore the historical.
Chomsky (1965) defined grammatical competence in terms of the language of (i.e. stringset generated by) an ideal speaker-hearer at a single instant in time, abstracting away from working memory limitations, errors of performance, and so forth. The generative research program has been very successful, but, one legacy of the idealization to a single speaker at a single instant has been the relative sidelining of language variation, change and development. More recently, Chomsky (1986) has argued that generative linguistics can offer a precise characterization of I-language, the internalized language or grammar of an individual speaker, but has little to say about E-language, 'external' language, which is an epiphenomenon of the I-languages of the individual speakers who comprise a speech community. Consequently, the study of language change within the generative tradition has largely focused on 'I-language change'; that is, the differences between I-languages or their corresponding grammars internalized by child language learners across generations. And within I-language change on the (parametric) properties of internalized grammars (e.g. Lightfoot, 1979, 1999). The generative approach to language change treats (major) grammatical change as a consequence of children acquiring different grammars from those predominant amongst the adults in the population, perhaps as a consequence of variation in the internalized grammars of these adults. However, theories of language variation, change and development will (minimally) require an account of how the E-language(s) of an adult population can be defined in terms of the aggregate output of these (changing) individuals.
As the written form is a foundational part of every aspect of social studies, it would seem logical that the E-language equation must be entered back into the prime question and one way to achieve this is through the assessment of grammaticalization as an epiphenomenon that cannot be, and should not be isolated from the diachronic view.
On the other end of the spectrum from strong claims about unidirectionality are arguments that there are so many counterexamples to unidirectionality that is cannot be considered a defining characteristic of grammaticalization (e.g., Janda 1995, 2001; several articles in Campbell 2001a). In a chapter entitled "Deconstructing grammaticalization" Newmeyer has proposed that "there is no such thing as grammaticalization," at least as a phenomenon independent of other changes (1998: 226). Many of the researchers who argue from this perspective are concerned that, even if unidirectionality were irreversible, including unidirectionality in the definition (as we have) makes the claim of unidirectionality uninteresting from a theoretical point-of-view (see Norde 2001 for detailed discussion). Newmeyer (1998), Campbell (2001b), Janda (2001), Joseph (2001), and others use this argument to claim that, although there is extensive evidence fro regularly recurring directional changes, grammaticalization should not be thought of as a "theory," in the sense of an explanation of a subject of study. Instead, they suggest, it should be thought of as the descriptive name of a frequently occurring epiphenomenon that can be explained by other factors that occur in language change anyhow. Such other factors are variously thought of as reanalysis (I. Roberts 1993a) or "downgrading reanalysis, appropriate semantic change, and phonetic reduction" (Newmeyer 1998: 260). (Hopper & Traugott 132-133)
Foundational aspects of grammaticalization assume that the changes that occur are occurring individualistically among those who speak and write in a given language and the language itself. Marrying the two is essential to a full understanding of the formation of change and essential to creating a better understanding of how language may change in the future. Though there may not be a general historical rule, those that do exist and especially the irreversibility of grammaticalization is essential to understanding such phenomena and language change.
A language change is shown to result from the cumulation of countless individual actions of speakers, which are not intended to change language, but whose side effect is change in a particular direction. Grammaticalization is a side effect of the maxim of extravagance, that is, speakers' use of unusually explicit formulations in order to attract attention. As these are adopted more widely in the speech community, they become more frequent and are reduced phonologically. I propose that degrammaticalization is by and large impossible because there is no counteracting maxim of "anti-extravagance," and because speakers have no conscious access to grammaticalized expressions and thus cannot use them in place of less grammaticalized ones. This is thus a usage-based explanation, in which the notion of imperfect language acquisition as the locus of change plays no role. (Haspelmath 1043)
The foundational idea of grammaticalization, therefore must not be isolated to a single time and/or place, reducing the overall message of the concepts to a snapshot of the creative process that is at play in the foundation of language change. Context, culture, social exposure and many other issues must be assimilated into the concept.