UPDATE! I mistakenly say that dictionaries and linguists are prescriptive. I meant to say descriptive. I hate how similar those two words sound. Anyways, dictionaries and linguistics are descriptive.
Key terms: language attitudes, dialect, regional dialect, sociolect, AAVE, idiolect, prescriptive, descriptive, prestige, overt prestige, covert prestige, standard language, SAE, accommodation theory, register, informal, formal, communicative competence