Lisa Trongprakob used to dread self-introductions. People often asked her to spell out "Lisa" as they couldn't understand her pronunciation "Li-tha." Growing up in Thailand, she began to learn English when she was just four years old and excelled in language exams at school. But when she came to the U.S. at 24 to study computer science at Cornell University, she found that her accent often got in the way of communication.

Now in her 30s, Trongprakob works at Google as a software engineer. And like many of her immigrant counterparts working at U.S. companies--or running them--she is expected to speak pristine, accent-free English. "I've always known that [my accent] is a problem," says Trongprakob. "In general, people here expect you to speak English very clearly."

That pressure has created something of a cottage industry in language instruction and accent modification classes among technology workers and international entrepreneurs in the U.S.

For these professionals, an inability to speak perfectly can cost them a promotion or a client. For entrepreneurs, in particular, speaking with an accent can make pitching investors or providing credible consultations untenable.

Taking Pride

"When someone presents in their native language, the result is much better," says David Paluy, an Israeli entrepreneur, who now lives in Palo Alto, California. "If I can't speak well, I will be ignored for sure." Paluy's company, EquityX, offers a platform that helps startups pay part-time workers with equity.

Indeed, "It's kind of a matter of pride," says Brian Hickey, director of Pace University's English Language Institute, which offers accent courses to the public in New York City. Many students, he says, already speak English well, "but they feel that they are not projecting professionalism."

Speaking with a blended Hebrew and Russian accent, Paluy was often asked during sales pitches to repeat certain words, including the word "entrepreneur." "The difficult part of being an entrepreneur is to pronounce it correctly," Paluy quips.

To overcome the language barrier, he took web courses at the Accent's Way, founded by Hadar Shemesh, a Tel-Aviv based teacher who charges $347 for a 10-week online program. Her students are typically non-native English speakers located in Russia, Philippines, India, South Korea, Brazil, and more.

Incubators like The Refiners also work with accent teachers to help foreign entrepreneurs prepare their pitches. Lisa Wentz, who launched the San Francisco Voice Center in 2008, holds seminars on both accent reduction and public speaking for entrepreneurs, who are often referred to her by their advisers at incubators.

Building Credibility

To be sure, accent reduction training has been vital for decades. Pace University's accent reduction workshops have been around since the 1980s. And naturally, actors and broadcasters have long looked to quash a Southern twang or acquire one, depending on the part.

The early 1990s gave rise to a number of lawsuits featuring employees who had either been fired or lost out on promotions, specifically, as a result of a foreign accent. Discrimination on the basis of national origin remains illegal under federal law. A business would need to be able to prove other reasons for dispatching or failing to promote an employee.

Even so, international knowledge workers still feel pressured to reform their speech patterns. In a 2010 study, psycholinguist Shiri Lev-Ari asked native English speakers and non-native speakers to record questionable statements like "Ants don't sleep." When audiences listened to the recordings, they rated the ones from native speakers as most credible and the ones from speakers with heavy accents as least credible.

It's unclear whether enthusiasm for Donald Trump's anti-immigrant rhetoric is having any kind of effect on accent modification in the U.S. However, accent teachers say that stricter visa requirements or more impediments to legal immigration could hurt their businesses. In the current atmosphere, many say it has become even more important for foreign workers to curb language ticks or smooth choppy accents.

Translating Value

For Trongprakob, the pressure to improve her speech began three years ago, after she decided to build a long-term career in the United States. She was promoted to technical leader at Google, a position that requires her to speak frequently in front of her team. Plus, she simply got tired of being asked to repeat herself in speeches.

She turned to Rochel deOliveira, a musician-turned-speech pathologist, who founded the New York-based American accent-training program, AccentsOff Speech and Voice Improvement. She teaches what she calls a standard American accent, or "unaccented" English usually associated with the educated class and broadcasters.

After launching as a one-woman shop in 2011, deOliveira's language modification business has grown to a seven-teacher crew who see about 250 clients each month. Typically, these people are immigrants who've come to the U.S. for work from countries such as China, Russia, Brazil, and India. They're employed in fields as diverse as technology to the law. Some work for large multinational companies like Google, Bank of America, and Credit Suisse, and some are entrepreneurs.

"They want to sound like they are not from anywhere," says deOliveira, who compiles a "survival list" comprised of words that each client commonly mispronounces but are critical in work and life. For Trongprakob, her current list includes statistics vs. statistically, economy vs. economics, contribute vs. contribution.

She said she often stresses the wrong syllables. "For example, it's 'stra-TE-gically,' not 'STRA-tegically," Trongprakob said. "And I still can't do 'pure.' I haven't graduated from that class yet."

At home, Trongprakob listens to audio clips recorded by deOliveira, who doesn't use a textbook but has designed worksheets for her students. One practice tongue twister reads, "Elaine and Wayne go to Maine everyday."

While pricey--at about $130 a session--Trongprakob describes her language classes as "therapeutic." "That's like two nice meals in New York City," says Trongprakob, who adds that the value she's getting is priceless. "If I can communicate clearly and people perceive me no less smart than I am, it's worth more than two meals."