Varaleiva wrote:In my understanding is that all languages have undergone creolisation processes, only one less while other very significant. By "creolisation" I understand language mixing and resulting change.
As I said in my first response, your understanding is false. All languages change--in fact, all living languages are in the process of changing right now. All languages undergo some degree of mixing as a result of language contact, although some (e.g. English, Japanese) obviously more than others (e.g. Navajo, Finnish). "Creolisation" doesn't refer to either of these phenomena. "Creolisation" describes a very specific process by which a new language comes into being in a more-or-less spontaneous fashion due to a catastrophic disruption in the process of transmission.
Let me try explaining it in another way: the ancestors of today's present speakers of Latvian also spoke a form of Latvian. So did their ancestors, and their ancestors before them, and so forth. As you go back each generation, you will find the language slightly different, but at no point is there a dramatic difference between the languages spoken by one generation and one coming before or after. A grandparent won't understand every word their grandchild speaks to them, but there is very little about their speech which they will find foreign.
That's not the case with creoles. Go back far enough in the history of, say, Haitian Creole or Papiamentu and suddenly the earlier generations aren't speaking a form of Haitian Creole or Papiamentu at all. They aren't speaking anything with a lexicon derived from European languages. They are speaking West African languages or Arawakan languages. Within a generation or two, there was a complete break between one line of transmission and the beginning of an entirely new one. It's not like what my ancestors experienced, where there was a period of stable bilingualism before the younger generation gradually stopped speaking German and Irish. The ancestors of these creole speakers were thrown into a situations where they had no common language with which to communicate and had to invent one.
That's what creolisation is. Your distinction between "primary languages" and "creole languages" simply isn't tenable. Once a creole language is born, it undergoes the same process of change, language contact and borrowing, and elaboration as any other natural language. (Some linguists, e.g. John McWhorter, believe that historical creoles can still be distinguished synchronically from non-creoles, but they're in the minority.)