Principle of linguistic inferiority refers to the tendency of speakers of the socially dominant group in a society to interpret speech of a subordinate group as linguistically inferior to that of their own.
This bias is likely to be found among the speakers of the ‘standard’ variety of a language due to the differences of various groups in their status and power relations. Linguists consider any dialect/variant of a language to be ‘fundamentally regular’ and worthy of its existence.