In the grand old days of Gershwin, if you said tomato and I said tomatoh, it meant we faced irreconcilable differences. You liked this and the other, while I went for this and that. The inevitable conclusion must be that we should just call the whole thing off.

It’s nearly a century since Ginger Rogers and Fred Astaire performed that number on roller skates (she in heels), but since then the language differences between left and right, or liberal and conservative, have become so much more exaggerated. Language is often used to signal belonging to a tribe rather than to communicate with others.