If I say ‘David Bellos has to be one of the smartest people now on the planet’, what language am I using? English of a kind; but scarcely the Queen’s, which – to judge from her public utterances – retains a careful insularity; mid-Atlantic schtick is not Her Majesty’s bag. The use, in England, of ‘smart’ meaning ‘super-clever’, as opposed to ‘well-dressed’, dates from the Sixties. It takes its tone and form from David Ogilvy’s Madison Avenue. ‘Has to be’ promises my personal endorsement. It is also remarkably difficult to translate, even into so adjacent a language as French. ‘D B doit être certainement un des gens les plus intelligents du monde’ does some of the work, but it lacks the American tang and it fails to render ‘has to be’ as daring the reader to say I’m wrong. ‘D B est un crack’ is closer, but also further away. Bref, even simple translation ain’t easy to do.