USC professor under fire after using Chinese expression students allege sounds like English slur

The University of Southern California, photographed in 2018.

(CNN)A business professor at the University of Southern California became the center of an international academic controversy last weekend, after ​the school administration received a letter accusing him of using Chinese words that sounded like an English racial slur. ​

The letter was not signed by any individuals, but instead by "Black MBA candidates c/o 2022."
CNN obtained a copy of the letter, but could not find an official USC group by that name or reach the letter-writers for comment.
    Professor Greg Patton of USC's Marshall School of Business was teaching a ​communications class via Zoom call on August 20, according to the university. An online video recording of the call, which USC confirmed was authentic, shows Patton ​discussing the use of pauses while speaking, and giving an example of how Chinese ​speakers use filler words.
    "In China, the common word is 'that' -- that, that, that, that," he said in the video, before using the equivalent Chinese term nei ge several times to demonstrate.
    The following day, a complaint was filed to the school administration, saying the term sounded like the N-word and that Patton had "offended all of the Black members of our class."
    Headshot for Greg Patton, Professor of Clinical Business Communication at University of Southern California's Marshall School of Business.
    "This phrase, clearly and precisely before instruction is always identifi