Why can’t you say chmlk? What makes a vowel?

In elementary school, we all learned the vowels of the English language: a, e, i, o, u and sometimes y. But what makes a vowel a vowel? Vowels and consonants are essentially two different categories of sounds that linguists use to better understand how language sounds work. The study of the sounds that human beings can produce is called phonetics. It’s a sub-speciality of linguistics.

According to phoneticians, a vowel is a speech sound that is made without constriction of the vocal tract. What does that mean? It means that when you say a vowel, the sound is not stopped by your tongue, teeth, or cheeks. Try it! When you pronounce all of the vowels, your mouth stays open, but for every consonant, your tongue hits your teeth or the top of your mouth.

The word vowel comes from originally from the Latin vox meaning voice. Consonant means “with sound” from the Latin com (with) and sonare (sound).

Every language has vowels, though some have more vowel sounds than others. Across many languages, all words have to have vowel sounds, but not all words have to have consonants. This is because the sound and volume of spoken language comes from the vowels. The consonants break up the sound that the vowels generate. That’s why it’s impossible to say a string of consonants in a row. By nature, consonants stop the air flowing through the vocal tract, which is why you can say a vowel as long as you have breath, but you can’t draw out a sound like “l” unless you break it up with more vowels, as in “lalala.” This is also why vowels sit in the middle of syllables. They give language form and rhythm.

Strings of consonants sound like parts of words in English. Think of the phrases, “hmm” or “hmph.” They are not complete words, even though they do have some meaning. Without any vowels in languages, we would be left with meaningless consonant strings. Although some languages, like Polish, can have as many as five consonants in a row, in English, we’re typically restricted to three, like str in strict.

Vowels and consonants are oversimplified categories, of course—sounds are in reality more complicated than that. Take sounds like “s” or “z,” which don’t need to be broken up by vowels to continue. Are they vowels or consonants? You can say “z” forever. It’s the onomatopoetic sound of bees buzzing, to give just one example. These sounds are a subcategory of consonants called fricatives, made by pushing air through a very small space in your mouth. And what about y? Y is an example of a semivowel. Learn more about the history of the 25th letter of the alphabet here.

English is a complicated language. What other facets of the English language stump you?