Wallace and Gromit help US actors speak the Yorkshire way

In California you are more likely to hear someone exclaim, "Cool, dude", than "Trouble at t'mill", but that could be about to change.

In preparation for the Los Angeles production of Alan Bennett's The History Boys, the American cast has been told to watch The Full Monty, Monty Python and Wallace and Gromit to perfect their Sheffield accents.

Set in a grammar school in the Yorkshire city in 1983, Bennett's award-winning play tells the story of a class of boys preparing for the Oxford and Cambridge entrance exam.

When the play transferred from London's National Theatre to Broadway, it retained most of the original cast, including Richard Griffiths, pictured below, as the overweight but inspiring English teacher Hector, a role he reprised for the 2006 film version.

While the production at the Ahmanson Theatre is directed by an Englishman, Paul Miller, union rules and immigration issues mean the students are played by actors from the United States.

A dialect coach, J B Blanc, has also been brought in to help them capture the Yorkshire accent. Mr Blanc, a coach, actor and director who grew up in rural North Yorkshire, has led the young actors on an unusual training scheme, including watching The Full Monty, the 1997 Oscar-winning film set in Sheffield and starring Robert Carlyle about six unemployed male steelworkers who form a male striptease act.

Mr Blanc also introduced them to "The Four Yorkshiremen", the Monty Python sketch in which four men attempt to outdo one another with tales of their hellish childhood, insisting in broad Yorkshire accents: "You were lucky ... There were 150 of us living in t' shoebox in t' middle o' road."

Most importantly, however, Mr Blanc used Wallace and Gromit to explain to the American cast how their mouths would have to move to pronounce Yorkshire vowels. Although the Aardman Animations characters actually live in Wigan in Lancashire, Wallace, who is voiced by Peter Sallis, has an accent from the Holme Valley of Yorkshire.

Mr Blanc told The Los Angeles Times: "An accent involves not only the sounds one has to make but the geography, the history.

"The problem they have is, this accent involves them using muscles they've never had to use. The American accent is lateral, flat; the back of the mouth doesn't have to work hard. Yorkshire is more horizontal, rounded at the back of the throat. There isn't a vowel sound that is similar to an American vowel sound."

The History Boys, which opened at the National Theatre in 2004, won the Olivier Award for best play. When it transferred to Broadway in 2006, it won six Tony Awards. Mr Miller said it was often easier to teach American actors to speak in a Yorkshire accent than British actors who speak with a different regional accent.