Why are tongue twisters tricky? (Part 2)

Oh, so in my last post I talked about the tongue part of tongue twisters. But, as I mentioned, the really interesting part of tongue twisters comes from the brain, not the tongue. It all has to do with lexical access.

Lexical access: The process through which a speaker or listener accesses their mental lexicon (i.e. the not-so-tiny brain dictionaries we all have and are all constantly changing).

If you were a computer, your mental entries on various words would be like files you needed to access. Like, if I write “kumquat”, you probably have some sort of mental entry for it. Even if you’ve never eaten a kumquat, you’ve probably seen them, so you have that mental image associated with the words–like a .txt file with a picture in it. So, once you hear or read “kumquat”, you need to rummage around until you find that file, then open it and access the information inside. And you do! In fact, you do it very, very quickly. You do it for every single word you ever read or hearand you do it in reverse for every word you ever write or say.

Brain Surface Gyri

This is your brain on language. Well, some of the bits that deal with language, at any rate.

So lexical access is a very important process. You need it for every single aspect of language use. The good news is, there’s a lot we know about lexical access! Remember when I talked about priming? That’s an aspect of lexical access. The bad news is, there’s a whole bunch we don’t know about lexical access.

(Is lexical access starting to sound like a fake word yet? That process, by the way, is known as semantic saturation.)

This is where tongue twisters come into play. (No, I hadn’t forgotten them.) Why? Well, it turns out that tongue twisters are a really good way to get at what happens during the lexical access process. Like many things that happen in the human brain, it can be difficult to study lexical access. Unlike physicists, linguists can’t break apart the mind to see what happens and figure out what’s going on. First, it would be deeply unethical. Second, when you break a brain open, it stops working. Sometimes, however, the brain does something weird. Like with tongue twisters. If you read my previous post, you know that the tongue itself can cause problems… but not enough to explain the most common errors, like saying “How can a clam cram in a clean cream can?” as “How clan a cam cram in a clean cleam can?”

In a 1999 study, Carolyn E. Wilshire found that there were two main contributors to making tongue twisters tricky. The first factor that made it easier to confuse sounds was whether the confuseable sounds were similar. There’s lots of technical reasons this is, but basically sounds can be grouped together and some sounds are more like other sounds. “t” and “d” are really similar, for example, whereas “k” and “m” are not really that alike. Unsurprisingly, sounds that are alike are easier to confuse. Basically, you reach for something that sounds similar, then realize that you made a mistake and try to correct your error.

The second factor was that it was easier to confuse sounds that were repeated. This is because you’re more likely to “reach for” something you’ve already gotten out once, even if it’s the wrong thing. Together, these factors make for some really awesome tongue twisters. Awesome for two reasons: the first is that they’re really, really hard to say. (Try moss knife noose muff!). The second is that we can use tongue twisters like these to help increase our understanding of the human mind. And that’s what it’s really all about.

Why are tongue twisters tricky? (Part 1)

For me, the best part of the 2009 Star Trek movie was the scene where Kirk tries to pick up Uhara in a bar. After she  says he probably doesn’t know what Xenolinguistics is, he replies:

The study of alien languages. Morphology, phonology, syntax. Means you’ve got a talented tongue.

Well. Four out of five isn’t bad. Linguists know about language, not the languages themselves–so tongue talents are a skill that linguists only develop tangentially. (Although, of course, a lot of linguists do end up learning the languages they work on.) But knowing about tongues is still pretty useful. For example, it helps explain why tongue twisters are so hard.

Rolled tongue flikr
Tongue rolling is actually probably not controlled genetically. That’s right, your introductory biology textbook lied to you.
Basically, your tongue is a muscle like any other muscle, and it has certain limits. For example, there’s just a certain upper limit to how fast you can type, knit or eat, you can only produce recognizable words so fast. In addition to speed, however, there are certain motions that are difficult to make. Linguists often refer to correctly producing a given sound as “hitting an articulatory target”, and that’s a useful metaphor. For each sound in your repertoire, your tongue (and other parts of your articulatory system) have to be in certain positions.

Exercise time! Try saying “s sh s sh s sh” and “t k t k t k”. In the first, the tip of your tongue should move from that little ridge in your mouth (just behind your front teeth) to behind that ridge. In the second, the “t” sound should be made with the tip of your tongue against the roof of your mouth, and the “k” with the very back of your tongue. (I’m assuming that you have the “sh” sound in your native language, otherwise this exercise might have been a little fruitless for you. Sorry.)

You might have noticed that it was a little easier to make the “t k” sound than it was the “s sh” sound. That’s because you’re using two different parts of your tongue to make the “t k” pair, so while one is making a sound, the other is preparing to and vice versa. On the other hand, if your only using the very tip of your tongue, you have to finish one task before you can move onto the next, so your rate of making sounds is much lower. It’s the same reason that assembly lines are so much faster–you don’t have the additional time it takes to switch tasks. (BTW, that’s why, if you play a wind instrument, you can tongue faster with “t k t k” than “t t t t”.)

Ok, so we have two pressures working against your ability to produce tongue twisters. The first is that your tongue can only move so fast. You can train it to move faster, but eventually you will (barring cybernetic implants) reach the limits of the human body. Secondly, you have limited resources to make sounds, and when sounds that draw on the same resources are produced too close together, they both become more difficult to produce, and the speed at which you can produce them is reduced even further.

And that wraps it up for tongues, because the dirty secret of tongue twisters is that they’re mainly actually brain twisters. But I’ll cover that in part two. That’s right: brraaaaaaains.