Four former Delta employees who were allegedly told by a manager not to speak Korean because it made other workers feel uncomfortable are accusing the airline in a lawsuit of discrimination after they were fired last year.

The employees — Ji-Won Kim, Lilian Park, Jean Yi and Jongjin An — were Delta customer service agents at Seattle-Tacoma International Airport who say they were reprimanded for speaking Korean, even though they were assigned to work flights to South Korea, according to their suit.

“Many other employees frequently spoke to each other in their native languages during their shifts and were not admonished or coached not to do so,” read the suit, which was filed May 31. The women began speaking publicly about the case this week.

The complaint says the women were told they were being fired in May 2017 for allegedly offering unauthorized upgrades to customers, which the women said was standard practice.

The lawsuit, initially filed in state court in Seattle but moved to federal court on Delta's request, also claimed the women were sexually harassed by another customer service agent and were retaliated against after complaining about it. The suit also said the harassment continued after two of the women reported it to Delta leadership.

The women's lawyer, Jennifer T. Song, said her clients want "a recognition that they were wrongly terminated,” as well as unspecified damages for economic and emotional distress and back pay.

Delta, through a spokesperson, said that while it does not tolerate workplace discrimination or harassment of any kind, it had looked into the women's allegations and found no violations.

“We take allegations of workplace harassment and discrimination very seriously, and our investigations into allegations made by these former employees were found to be without merit,” the airline said in an email. “These former employees were unfortunately but appropriately terminated because the company determined they violated ticketing and fare rules. Delta is confident that these claims will ultimately be determined to be without merit.”

The lawsuit also claimed that the four women — all of whom were born in Korea and immigrated to the U.S. — were never offered additional pay to make announcements in Korean, while Delta employees of other national origins who spoke other languages received this benefit.

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