The word “layoff” appears nowhere in this report. The words used are “fired” “dismissals” and “firing”. This is a completely different activity than laying off.
David Foster Wallace wrote about the relationship between Standard Written English and social power structures in America. See "Authority and American Usage" or its reprint in Harper's, "Tense Present".
Had to fact-check that opening remark about Oakland being half African American. Sounded a little high but the 1990 census does show 44% Black. By current census estimates it's only 26%.
That aside, while it is cute that people make academic studies of this language, as a resident of Oakland I agree with the reactionaries that it should be exterminated instead. Recently when I was riding the bus, a woman on the bus loudly announced that "all dem bitch-ass niggas be hella gay". It does not matter to me that she meant "those people are habitual homosexuals" instead of "those people are currently homosexual". All I know is the language and the culture associated with that language have no place in public life or public school.