Rupert Cornwell: Twitter dialect says you are what you tweet

We British pride ourselves on our array of regional dialects and idiom – not like those Americans, who all speak the same. Well, maybe not all of them. There's the south of course, with its slow drawl, and idiosyncratic pronunciation and turns of phrase. And then you've got New Jersey/New York, as used in The Sopranos and countless Mafia movies, and doubtless by all those mobsters (sorry ...