Spot on: Open your mouth, stick your tongue out, and use a toothbrush or your finger to find exactly where your gag reflex is.

To find out how having an air sac changed the sounds produced, Dr DE Boer created plastic models of the mouth, tongue and throat and forced air down them to produce different vowel sounds.

Will you start out sweet as sugar candy and then suddenly, miraculously, like a bolt from the blue, find that sharp little tongue of yours?