"In one of Kinzler’s studies, kindergartners were shown a clip of a white girl speaking English and then clips of two adults, one a Francophone white woman and..."

"... the other an Anglophone Black one. The children actually supposed that the white girl would grow up to be the Black woman, so deep-seated was their sense of language as marking identity. Fourth graders, on the other hand, had internalized race as the deciding factor.... Amid our discussions of racism, sexism and even classism, we don’t spend much time thinking about the ways we can be biased when it comes to how people speak. It is, however, one of the last prejudices permissible in polite society. As Kinzler notes, 'Linguistic bias is part of our basic cultural fabric. It is so ubiquitous that we don’t even think about it. It’s sanctioned by the law, it’s allowed by culture, and it’s practiced so frequently that people do not even realize when it is happening. Linguistic discrimination is seen as normal and typical, and because of this, it flies beneath the radar.'"

From "The Biases We Hold Against the Way People Speak" by John McWhorter (NYT) — reviewing the book "HOW YOU SAY IT/Why You Talk the Way You Do" — and What It Says About You" by Katherine D. Kinzler.