And That’s the Tooth!

I had some dental work recently, and that got me thinking about the apparently strange names we give to our teeth in English.

Using standard terms, you have four types of teeth: incisors at the front, molars at the back, bicuspids between them, and between them and your incisors, you have your cuspids, or canine teeth. The reason they’re known as canine teeth is clear if you’ve ever owned a dog, as in dogs they’re much longer. And scarier. More specifically, the two upper canine teeth are known as eye teeth. You might be expecting some convoluted etymology for the term, but the simple reason is that (for most people) they’re directly below your eyes. So that’s that! They’re also apparently linked to the eyes in traditional Chinese as they’re believed to be on the same meridian.

Some of you may have had trouble with your wisdom teeth, those troublesome third molars which arrive quite late. And that’s the simple origin of their name. Scientists believe that these late-emerging teeth were our ancestors’ answer to the increased wear and tear on their teeth from their diet of rough food, and they’re called wisdom teeth because they appear later in life than your others, when you should be wiser.

Before you need to worry about wisdom teeth, there are your first teeth or deciduous teeth, to give them the correct dental definition. You probably know the word deciduous in relation to trees that lose their leaves in their winter, just as we lose our deciduous teeth as we progress through childhood. Most European languages call them milk teeth, for another very simple reason: they resemble the colour of milk, especially in contrast to the darker temporary teeth which replace them.

So, it seems that the etymologies of our names for teeth are pretty straightforward. But there are a couple of interesting tooth-related idioms. If you cut your teeth on something, it means you come of age by doing it, become mature. It’s an idiom that’s always sent a shiver down my spine, as it makes me vividly picture a knife cutting my teeth, which makes those my-teeth-are-falling-out dreams seem mild. But the idiom actually refers to when a baby’s teeth first emerge and cut through the gums. Strictly it should maybe be cut your gums then, but then there are a lot of ways to do that, so the meaning wouldn’t be as obvious.

And of course you can say something is as rare as hens’ teeth. And the simple explanation of that is that hen’s teeth obviously don’t exist, and are therefore pretty rare to say the least.

The word teeth itself though, is quite interesting, especially as it’s a rare irregular plural. The reason we say teeth instead of tooths is because of something called I-mutation. This is quite complex-sounding, but is kind of straightforward. Basically, it involves shifting the sound of a vowel slightly in certain situations, specifically shifting from a “back” produced at the back of the mouth sound to a “front” I sound produced nearer the front of the mouth. Think of the difference between do and doing.

In Proto-Germanic languages, plurals would be formed in similar ways to now. Man would become something like manniz. To make that easier to pronounce though (avoiding a back syllable followed by a separate front one), people would use a shorter, i-mutated sound, more easily sliding into the second syllable by both vowel sounds being produced closer to the front of the mouth. This made it sound more like menniz, and this eventually became men, with the changed vowel sound standing for the plural form. We also have to change the sound of the first syllable between woman and women so we can have two front syllables together in both the singular and plural forms. This is also where we get teeth from, and other irregular plurals like mice.

So there is something interesting about teeth after all!

4 thoughts on “And That’s the Tooth!

  1. […] Man/men, woman/women, and child/children cause similar confusion. I always like to remind students that they’re all words to refer to people, to help them remember them. That they have such a fundamental meaning for us is also probably why these old plural forms haven’t changed much over the millennia, despite some fundamental changes in the English language. […]


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