It wasn’t only Londoners born near a certain church in Bow who grimaced when Dick Van Dyke’s chimney sweep, Bert, opened his mouth in the 1964 musical, Mary Poppins, an offence for which he apologised more than half a century later. But if Van Dyke murdered the cockney accent, it seems Londoners, and southerners more broadly, are among the worst at spotting people mimicking their accents, with northerners, Scots and the Irish performing better. Researchers at the University of Cambridge tested how well volunteers in the UK and Ireland could spot people faking accents after hearing two to three second audio clips. The volunteers were asked to judge sentences constructed to emphasise differences between seven accents, namely the north-east of England, Belfast, Dublin, Bristol, Glasgow, Essex and received pronunciation (RP). For example, “He thought a bath would make him happy”, reveals southerners who turn “bath” into “barth”. People who heard any of the fake accents spotted them nearly two-thirds of the time and, unsurprisingly, the hit rate was typically higher when a person heard someone faking their own accent. But the study found marked regional differences. When played recordings of people imitating accents found in Scotland, the north-east of England, Ireland and Northern Ireland, listeners from those regions identified 65% to 85% of the fakes. In contrast, when those from London, who mostly spoke RP, and those from Essex heard people faking their accents, they spotted them 50% to 70% of the time. Bristolians fared only slightly better, rooting out 50% to 75% of the fakes. “We found that people from further south in the UK were more likely to be worse at this,” said Dr Jonathan Goodman, an anthropologist and first author on the study. Are southern English accents simply easier to fake than others? Goodman thinks not. Instead, he sees cultural evolution at work. A person’s accent is a signal of their social identity, and the history of tensions across the UK could have brought northerners, Scots and others closer together, making them more attuned to outsiders. “Let’s say you’re from an area in the UK that doesn’t have a good relationship with the capital,” Goodman said. “There might be a negative out-group sentiment that leads you to focus more emphasis on your social identity, on your accent. It’s speculation, but it’s my best guess at what’s happening.” Details are published in Evolutionary Human Sciences. A similar effect has been seen before. In 1963, William Labov, a US linguist, found that the residents of Martha’s Vineyard in Massachusetts started emphasising their accent when they were overrun with wealthy summer visitors. Dr Alex Baratta, a reader in language and education at the University of Manchester, said it was worth asking why groups such as the Irish might feel a need to be on the alert to outsiders. “A central reason is to indeed protect themselves from outsiders, especially given attacks, literal and figurative, such as Irish jokes told in fake Irish accents, over the years from outsiders,” he said. “This might help explain African Americans’ arguably being more able to detect individuals, black or white, affecting the sounds of Ebonics, a dialect spoken by some African Americans. “Certain accents come with more emotional baggage than others, based not on sounds, but on the negative stereotyping of the speakers. Thus, such speakers reinforce, and take pride in, how they speak, leaving their accent a social marker not to be messed with, especially if it has been mocked by outsiders.” For Van Dyke, and more recently Russell Crowe, who lost it when a Radio 4 presenter noticed a hint of Irish in his Robin Hood, accent is only the start. “It’s the impersonation of the entire identity,” Goodman said. “To be an effective actor you need to capture the identity more fully than just the phonemes that relate to the accent itself.”