The latest research from Zurich UK found that 36% of workers with a regional accent felt judged for it at work.
31% said they felt they needed to change or soften their accent in the office to sound more professional.
14% had taken elocution lessons to avoid judgement.
13% of people with a regional dialect said they had heard negative comments about the way they speak, or had their accent mimicked by a recruiter or hiring manager.
16% said they suffered from accent anxiety which stopped them speaking up at work.
19% believed their accent had held them back in their career and made them feel less intelligent than their colleagues.
23% felt most self-conscious about their accent at work, while 32% said people made assumptions about their character or ability based on how they sound.
Received Pronunciation (RP) was rated the most suitable accent for the workplace at 76%.
The Edinburgh accent followed at 61%, Welsh at 53%, Yorkshire and Northern Irish both at 49%, Manchester at 47%, West Country at 46%, Newcastle at 43%, Glasgow at 42%, Birmingham at 37%, Liverpool at 35%, and London Cockney at 32%.
Steve Collinson, chief HR and sustainability officer at Zurich UK, said: “As a proud Mancunian, I wear my heritage with pride.
“It’s disappointing that many of those with an accent feel that they can’t bring their authentic selves to work.
“When people feel the need to hold back or mask who they are, you never truly see their best as they remain guarded and in survival mode, rather than able to thrive.”
Collinson added: “Those with more traditionally accepted and ‘polished’ accents may not always realise how different colleagues with stronger regional accents experience the workplace. That’s why education matters.
“We need to help people recognise unconscious bias, challenge stereotypes, and create environments where every voice – whatever the accent – is respected and valued.”