He is the leader of a gang of "droogs" - the name given to his friends in the book's language Nadsat - a mix of Russian and English slang.

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We spent one afternoon with well-dressed students at Kim Il Sung University and later at a foreign language high school where very bright 16-year-olds were learning English complete with American slang.

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Baker is an expert on English, especially on slang.

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While learning American idioms has always been challenging, texting, email and social networks have generated a tidal wave of new slang and abbreviations in English.

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"He didn't speak English that well and with my Yorkshire slang, I think that made things difficult too, " said Toseland.

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If you run out of money, you can walk across the street to an ATM that offers Cockney rhyming slang as an alternative to English.

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At Kennesaw State University in Georgia, the Intensive English Program doesn't teach a slang expression until it is in use for more than one generation, says David Johnson, a professor of English and director of the program.

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"'Kicking ass' is acceptable vulgarity, " says Michael Adams, professor of English language at Indiana University-Bloomington and author of Slang: The People's Poetry.

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The New Shorter Oxford English Dictionary (as opposed to the Old Longer One) pegs the birth of the slang sometime between 1930 and 1969.

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