Decreolization is a phenomenon whereby over time a creole language reconverges with one of the standard languages from which it originally derived. First proposed by Keith Whinnom at the 1968 Mona conference, the concept has come under fire in recent years from such linguists as Bickerton and Rickford since at its inception it sought to overturn long-held elements of the theory of creole continua.
Decreolization is a process of homogenization a creole language may undergo when in contact with one of its parent languages, particularly if the parent language is ascribed a prestige value. To put it another way, in decreolization, the influence of the superstrate language dismantles influences from substrate languages.
If one views pidginization as a process of simplification, reduction, and admixture from substrate languages, and creolization as the expansion of the language to combat reduction, then one would view decreolization as an attack on both simplification and admixture.
As languages remain in contact over time, they inevitably influence one another. Typically, the language with higher prestige (most often the lingua franca) will exert a much greater influence on the lower prestige language (the creole). This leads to the reintroduction of complexities, irregularities and redundancies into the creole from the source language. Elements of other sources begin to disappear as there is less and less linguistic territory for them to cover. It is theorized that eventually the creole will resemble the source language to such a degree that it can then be called a dialect of that language rather than a separate language at all.
Another name for a near-fully decreolized language is a “vestigial post-creole.”
Jamaican Creole, which exists in continuum with Jamaican English and Standard English,  Jamaican Creole is much more akin to standard English than most other English-based creole languages. Also, the creole is recognized by Jamaicans as “bad English,” the more standard varieties being more common in educated and urban settings, so there is conscious effort made to alter the speech of poorer, rural folk towards the English norm. 
citation needed] According to this viewpoint, AAVE had originally developed from Pidgin English, a pidginized form of English characterized by syntactic structures and words from West-African languages. Pidgin English was used as a means of communication between English-speaking Europeans among Africans, and among Africans whose languages were mutually unintelligible. This then developed into a creole language which, after hundreds of years of contact with standard varieties of American English, had undergone decreolization to an English mesolect. Proponents of this viewpoint[who?] label AAVE a vestigial post-creole.[
This view is not without controversy, as citation needed][
Decreolization processes occurred in creoles ranging from Brazil in South America as well in Africa, to Macau and Daman in Asia. The Asian and American creoles existed in continua with forms of Portuguese and underwent a process of decreolization when the Asian places were still overseas provinces of Portugal, and from the 18th century when the línguas gerais were forbidden by Marquis of Pombal to about one century after the Brazilian independence along in the Americas. These older processes can best be seen or studied in Daman and Diu Portuguese and Macanese Patois, which converged with Standard Portuguese.
In Africa, these are contemporary processes in post-independence Africa. In Cape Verde and Guinea-Bissau the creoles are dominant over Portuguese, but undergoing decreolization processes, leading to the development of soft creoles in both Cape Verde and Guinea-Bissau and post-creole continua with noncreolized Portuguese. In São Tomé and Príncipe, the situation is different from Upper Guinea as noncreolized Portuguese is dominant over the creoles, and children are intentionally raised in Standard Portuguese by their parents, leading to the younger generations in Principe Island not even being able to understand the island's creole or not valuing it.
- Estudo do Léxico do São-Tomense com Dicionário Carlos Fontes - Universidade de Coimbra.
- Trudgill, Peter (2000). Sociolinguistics: An Introduction to Language and Society, 4th ed. Penguin.