Sixty-two per cent of Americans got 'embarrassed' wrong, against 54 per cent of Britons who struggled with the word in a survey last year
Americans are worse at spelling than Britons, with more than half unable to spell "embarrassed", "liaison" and "millennium".
Despite the popularity of school spelling bee competitions, adults in the US fared poorly in a survey comparing how English speakers on both sides of the Atlantic deal with commonly misspelt words.
Sixty-two per cent of Americans got "embarrassed" wrong, against 54 per cent of Britons who struggled with the word in a survey last year.
Adults in the US performed less well on most of the ten words tested, including millennium (52 per cent wrong, against 43 per cent in UK), liaison (61 per cent to 54 per cent) and "accommodation" (42 per cent to 36 per cent).
Only "definitely" and "friend" were spelt correctly by more Americans.
Professor Edward Baranowski of California State University said that the results reflected the "horrific" drop-out rates of US high schools.
"This certainly puts an eventual strain upon the universities, which must devote lots of resources to remedial education," he said.
Jack Bovill of the Spelling Society, which commissioned the research, said the high inaccuracy rates in both countries showed the need for the English spelling system to be modernized to improve literacy.
"When asked, only a quarter of adults thought they had a problem with spelling. The answers in the test prove that this is far from the case," he said. "What is holding the UK and the USA back is the irregular spelling system."
The US survey involving a sample of 1,000 adults was carried out online by Ipsos MORI last month, with the method based on a survey of 1,000 Britons in April last year.