bidialectalism

noun

bi·​di·​a·​lec·​tal·​ism ˌbī-ˌdī-ə-ˈlek-tə-ˌli-zəm 

: facility in using two dialects of the same language

also : the teaching of Standard English to pupils who normally use a nonstandard dialect

bidialectal

ˌbī-ˌdī-ə-ˈlek-tᵊl 

adjective

Word History

First Known Use

1958, in the meaning defined above