A, E, I, O, U, and sometimes Y … and W? Yes, the letter W can behave as a vowel. It’s time to level up your Scrabble game, people. And, to all our grade-school peeps out there, get ready to knock the socks off your Spelling teacher.

First, what is a vowel?

A, E, I, O, U, Y, and, as we’ll see, W, are called vowels, but let’s get technical. They are symbols (letters) that represent a special type of speech sound called a vowel.

According to phoneticians, a vowel is a speech sound that is made without significant constriction of the flow of air from the lungs.

In making vowels, the tongue can be at various heights in the mouth (e.g., high, mid, or low) and at various positions (front, central, or back). The lips can be variously rounded (cf. a long O and E). Vowels can vary in pitch and loudness, too.

If you do restrict or close your airflow in a significant way, you’re making a consonant. Where that restriction or closure occurs in your vocal tract determine what consonants you are making. B sounds are produced by bringing the lips together, for instance (bilabials). K sounds are produced by bringing the back of the tongue up to your soft palate (velars).

What about W?

W is a rebel: it defies categories. To put it simply, it’s a little bit of both, vowel and consonant.

Linguists call it a semivowel or glide, “a speech sound having the characteristics of both a consonant and vowel, especially W in wore and Y in your and, in some analyses, R in road and L in load.”

Nope, this ain’t your Spelling teacher’s alphabet, folks.

In English, W can behave this way at the beginning of a syllable, where it’s followed by a full-fledged vowel (e.g., wonderful). It can also behave this way as part of a diphthong (which is a vowel plus a glide), as in How now, brown cow?

Back in Old English, W was represented by an altogether different symbol: Ƿ/ƿ, called wynn. It was gradually replaced by the Norman (French) double U, which was literally two U‘s back to back, uu, hence its shape … and name, double-u!

… and then there was Welsh

The Welsh language is a Celtic language still spoken in Wales—and, fun fact, in a settlement in Argentina. And, it is perfectly happy using W (and Y, along with the other usual suspects) as a vowel.

English has borrowed a precious few words from Welsh that feature W as a vowel. A cwm, pronounced [koom] or [kuhm], is “a steep-walled semicircular basin in a mountain, sometimes containing a lake; a cirque.” A crwth, pronounced [krooth] and also spelled crowd, refers to ancient Celtic musical instrument. In both words, W stands for the same sound that oo represents in boom or booth.Cwm and crwth are very rare words in English—and all the rarer for the way they showcase W as a vowel.

Are there words without any vowels?

Slavic languages, such as Czech, are famous for the long strings of consonants their languages allow, like this Czech tongue-twister: strč prst skrz krk (“stick a finger down your throat”). In Slavic languages, a certain articulation of R can behave as a syllable all on its own.

This can called be a syllabic consonant, which can fill the vowel slot in a syllable. English can have them in the final syllables of words like bottle and button, among other environments. To put it simply, L, R, M, N, and the –ng in sing can have vowel-like properties and be syllabic.

English does have some interjections it spells without vowels (and vocalizes without true vowels) that are considered words, such as: brrr, hmm, shh, tsk, pfft, or psst. These are considered onomatopoeia, and imitate sounds we make to perform different actions, such as indicating we’re cold (brr) or demanding quiet (shh).

Now, we think you’re ready to pronounce the name of this Welsh town: Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch.