Four years ago, Elizabeth took a "Business English" course to communicate better with her colleagues. 

But the 35-year-old Taiwanese professional who lives in Singapore said they still ridicule her accent. 

So she's now thinking about taking more courses, with two goals in mind: to improve her English pronunciation and "remove" her native accent, she said.

"I think my Chinese accent is really annoying to others," said Elizabeth, who asked that CNBC not use her real name to protect her employment.

"I do think [removing it] will be beneficial for my personal life and help me to perform better at work."

Lost opportunities

Globally, nearly one in five workers say they feel they've been passed over for business trips because of the way they speak, according to an SAP Concur report published in June.

The results were most pronounced in Asia-Pacific, especially Australia/New Zealand (31%), Taiwan (26%) and Singapore/Malaysia (25%).

But some non-native English speakers have trouble just getting their foot in the door.

A study published in 2022 found that job candidates who speak with "standard accents" — that is, the accent generally accepted in a given region — are more likely to be hired. The research found this was due to a perception that other accents thwart communication, to accent prejudices — or both.

"Disentangling these two explanations is not easy," Jessica Spence, a postdoctoral researcher at The University of Queensland and one of the study's authors, wrote in an article on The Society for Personality and Social Psychology's website.

People may rationalize not hiring an accented speaker because of concerns about their communication abilities, when — even if unconscious — the decision may be rooted in underlying prejudices, she wrote.

The study — which analyzed 27 other studies on this topic — found that job candidates' comprehensibility, or how easy they are to understand, did not affect whether they got a job offer.

"What was related to hiring decisions, however, was judgments of the candidates' perceived social status: We found that candidates who spoke with non-standard accents were rated as less competent and less intelligent," she wrote.

The study also found that accent bias was far more pronounced for female job applicants, as well as for those with foreign accents, than those with regional ones.

Are language courses a solution?

That leaves professionals who work outside of their home countries, like Elizabeth, in a bind, which is why she said she's now considering paying for accent reduction classes at the New York-based company Accent Advisor.

The company teaches "the Standard American Accent … that you hear on American news programs and in educated circles," according to the website.

In an email reply to CNBC queries, the company said, "The goal of accent training is not to eradicate accents, but to empower individuals to communicate more effectively and confidently while preserving their unique cultural heritage."

One-on-one online sessions are 25 minutes long and start at $18 per lesson, according to its website.

Others undergo training provided by their organizations, said Regina Kim, an assistant professor at Fairfield University's Dolan School of Business. 

"If employees feel that their accents are impeding them … training may be helpful, especially for those who feel that their heavy accents get in the way of communicating with others," she said. 

Tracey Derwing, professor emeritus at the University of Alberta, told CNBC that training can be conducted by a trained language teacher or speech language pathologist. But accent reduction courses that promise to get rid of a certain accent in a short period of time are more popular, she said.

Brad Harris, a professor of management at HEC Paris business school, cautioned that it may not be reasonable or healthy to encourage employees to change their accent, if it's a strong part of their identity.

"In a lot of ways, this is similar to the idea of 'code switching' which is exhausting and unsustainable for employees," he added. 

Ritu Bhasin, leadership specialist and author of "The Authenticity Principle," agreed, telling CNBC: "It horrifies me that companies would train people to anglicize their accent — that is a direct reinforcement of … racism."  

A useful tool?

But Elizabeth said she sees such courses as a way of "taking control" of her situation. 

"I don't feel like I'm removing part of myself. My intention is to communicate better with other people and to quickly gain trust at work," she said. 

Elizabeth likens learning an American accent to "just one of the tools" in her arsenal — one she can deploy when needed.

"It is convenient to say or criticize such courses, but that's forgetting real problems that I am facing every day," she added. 

"People are already biased and prejudiced no matter what," she said. "If everyone is really so genuine and accepting of each other, we wouldn't even be talking about this."

The role of companies

Even so, Kim said, non-native speakers shouldn't have to change the way they speak to satisfy others' biases.

"The responsibility for interrupting racism in the workplace is on leadership, not the employee who's actually experiencing it," Bhasin added. 

For employers and organizations, it's crucial for leaders to have bias-disruption training, Bhasin said.

"I'm sure that many leaders don't even realize that accent-based bias exists," she said.

"We need to teach how bias shows up in everything from recruitment practices, to work allocation, from mentorship to compensation decisions and succession planning." 

Based on Kim's research, role-taking simulations — where native speakers are asked to speak in a foreign language and listen to their own speech — is effective.  

"Many interviewees claimed that native speakers lack empathy because they do not know what it feels like to work in a foreign language on a daily basis," she added. 

The more one is exposed to an accent, the easier it becomes to understand it. So companies can also encourage teams to work together for longer periods of time, Kim said. 

Plus, "as team members collaborate over time, they have more opportunities to exchange personal, idiosyncratic information," she said. "Consequently, surface-level differences — such as ethnicity, gender and language — become less important in defining a person."

Send them on that trip

Ivona Hideg, an associate professor in organization studies at York University, said companies should not shy away from sending individuals with accents on business trips.

"What managers tend to do is what we call third-party prejudice accommodation," she said. "They're saying: 'I have no prejudice against you, but my client does. I'm not going to send you because of my client.'"

But that only perpetuates prejudice and stereotypes, she said. "Managers are guilty of prejudice, as much as they'd like to think they're not."

Ultimately, all organizations have an incentive to address this issue, said Harris. 

"If talented workers with non-native accents don't see opportunities to advance and grow … they won't stay long," he said. 

"Leaders need to have the courage to say: 'This is the best person for the job,'" he said. "We're not going to indirectly license the stereotypes or stigmas our customers might hold.'" 

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