THE Shorter Oxford English Dictionary, the scaled-down, two-volume version of the mammoth 20-volume O.E.D., just got a little shorter. With the dispatch of a waiter flicking away flyspecks, the editor, Angus Stevenson, eliminated some 16,000 hyphens from the sixth edition, published last month. “People are not confident about using hyphens anymore,” he said. “They’re not really sure what they’re for.”