With Mark Lawson. As queues form for the largest-ever show of Leonardo da Vinci's paintings at the National Gallery, artist Tom Phillips reviews and considers whether the exhibition justifies the hype. At just 33, Maltese singer Joseph Calleja is tipped as one of the most promising tenors of the 21st century. He talks about his new album and his singing ambitions. Linguistics specialist David Crystal has selected 100 words which he feels best illustrate the huge variety of sources and events which have shaped the English language. He elaborates on some of his choices, showing how, for example, hello is a relatively new invention - whereas unfriend is nothing like as modern as we think. Producer Lisa Davis.