basilect

1. (sociolinguistics) A variety of a language that differs substantially from the standard form, and is only considered suitable for very informal contexts by speakers.Examples: "The highest level of good English has been called the acrolect; the lowest level of poor speech, the basilect; both are contrasted with the matrilect, the general native language."; "In both regions English is used extensively, the spoken form ranging from, in the language of linguisticians, the basilect to the mesolect and the matrilect or acrolect (prestige English) ."; "If only the basilect is a true creole, then the mesolect is relegated to limbo -- not a creole, certainly not a standard."