I love busting out a French subjunctive in pursuit of better restaurant service, so it’s a joy to discover there’s a neuroscientific upside to being multilingual It’s hard to pick a favourite PG Wodehouse line, but the one I’m perhaps most fond of is this: “Into the face of the young man who sat on the terrace of the Hotel Magnifique at Cannes there had crept a look of furtive shame, the shifty hangdog look which announces that an Englishman is about to speak French.” It’s funny, but it also…