There's a whole class of sounds that we use to fill in the middle of our syllables, to carry the weight of all the other sounds around them: vowels. Vowels are the loudest, most sonorous sounds we have in language, and if one of them is around, it always heads up its own syllable. But how do we define vowels? Well, like with consonants, if we want to define vowels in terms of how we make them, we can do it using a few different parameters. But vowels are characterized by having free airflow through the vocal tract, so the characteristics to look for when it comes to vowels are different.
For your simple vowel, when we look at them in the International Phonetic Alphabet, we care about three things: tongue height, which measures how far from the top of the mouth the tongue is when you make the vowel; tongue backness, which is how far forward or back in the mouth your tongue is during articulation; and lip rounding, which unsurprisingly is whether your lips round while you're pronouncing the vowel or not. If you have these three different pieces of information, you can find what vowel you're looking for.
Not all languages have the same number of vowels, and from a phonetics perspective, there are a few different reasons that have been proposed about why that might be. We discuss in the video a tension between wanting to have clearly defined categories, so you won't mistake one vowel for another, with the need to have a large number of words. Having more vowel phonemes means that you'll have more essential sounds to build more words from, but it makes it more likely you'll mistake one sound for another. There are a number of ways that languages can have more vowels than just changing where you pronounce them, though, and we address one: diphthongs, which are vowels that are made by aiming at two different vowel articulation areas over the course of the production of the sound.
We'll have extra materials comparing diphthongs to vowels in hiatus (or two vowels next to each other) up later this evening! If you're seeing this, thanks for getting it so early, and we'll fix this soon.
So how about it? What do you all think? Let us know below, and we’ll be happy to talk with you about vowels in all their sonorous glory. There’s a lot of interesting stuff to say, and we want to hear what interests you!