If people are ignored because of their inability to speak standard English, what have they encountered?

a. language bias
b. language variety
c. language prejudice
d. language snobbery
Are these real phrases? I don't know where to look them up to try to answer this question.

It looks as if a, c, and d would all be correct.

Google these phrases. I looked for two of them and found both.

it sounds to me like the answer is language prejudice

I think it's language prejudice.

b. language variety

b c d a

It's Language Prejudice. To answer another question of yours, yes, all of those are real phrases.