creolize
Concise Oxford English Dictionary © 2008 Oxford University Press:
creolize /ˈkriːəlʌɪz/ (or creolise /ˈkriːə(ʊ)lʌɪz, ˈkrɪɒl-/)
▶verb transform (a language) into a Creole.
– derivatives
creolization /-ˈzeɪʃ(ə)n/ noun.
creolization /-ˈzeɪʃ(ə)n/ noun.
'creolize' also found in these Oxford entries:

