A mouthful of [d]

December 10, 2011

In an essay about The King’s Speech for the Fortnightly Review, I wrote that the very familiarity of speech means we easily overlook how amazing its mechanics are. This occurred to me often while reading J.D. O’Connor’s superb Phonetics, a Pelican Original from 1973.

The book has a lovely paragraph on how the [d] sound in do is articulated. Complete description of such a sound is impossible because it would require mentioning an infinite number of features, so in general we note only those features that “seem to contribute substantially to the sound”.

Some of the following terminology might be unfamiliar, in which case refer to this diagram of the human vocal tract. Here, then, is [d]:

the lips are somewhat rounded (ready for the following vowel); the teeth are close together; the soft palate is raised; the tongue-tip is firmly in contact with the alveolar ridge and the sides of the tongue are in continuous contact with the sides of the palate; the back of the tongue is raised to approximately the close vowel position (again ready for the vowel); air under pressure from the lungs is compressed within the completely stopped mouth cavity and pharynx; the tongue-tip (but not the sides or the back) then lowers suddenly allowing the compressed air to escape with a slight explosion; just before the explosion the vocal cords start to vibrate in normal voice and continue to do so into the vowel.

Professor O’Connor says that although this description may seem quite comprehensive, it is very far from complete. But it serves its basic and practical purpose. [Edit: Note the two references to readiness for the following vowel. The mouth assumes different shapes for [d] depending on what comes next. To see (or feel) this for yourself, prepare to speak do, da and dee but stop before the vowel.]

It’s also a very pleasing account of an act most of us perform more or less identically, yet uniquely, every day without a moment’s thought. Think of how much exquisite unconscious coordination goes into a full sentence, or a week’s worth of conversation. How fortunate we are to have this facility.

O’Connor (1919–1998), known familiarly as “Doc”, taught phonetics at University College London; John Wells’s obituary in the Guardian describes his lectures as “witty and effortlessly informative”, which I can believe, and his writing as “elegant and readable”, to which I can attest.

A list of O’Connor’s many publications may be found on Jack Windsor Lewis’s website.