Is the w in cow a vowel or a consonant?
Assuming it is considered a vowel, would it likewise be so in how?

I learned that the vowels are "a, e, i, o, u, and sometimes y."

If w can be a vowel, what other letters can be vowels?
What is the definition of a vowel?

By the way, I know w can be a vowel, for example in the word cwm, described in the OED as:

A valley; in Physical Geogr., a bowl-shaped hollow partly enclosed by steep walls lying at the head of a valley or on a mountain slope and formed originally by a glacier; a cirque.

  • 11
    But "cwm" is not an English word; it's borrowed from Welsh. The two languages use most of the same typographic characters (so written Welsh looks superficially like written English), but their sound values are very different. "W" is a vowel in Welsh, not in English. The English equivalent of "cwm" is "coomb", which I (an American speaker) have only ever seen in The Lord of The Rings.
    – MT_Head
    May 15, 2011 at 21:15
  • 8
    I think this is a duplicate of a question that's come up before. From a linguist's point of view, the answer is essentially "this is a pointless question, because vowels and consonants are sounds, not letters". May 15, 2011 at 21:15
  • 2
    @MT_Head: Remember Koom Valley! May 16, 2011 at 3:12
  • @Andrew - I had to Google that. I haven't read nearly as much Discworld as I'd like.
    – MT_Head
    May 16, 2011 at 3:51
  • 3
    Is the 'gh' in Edinburgh a vowel? Oct 4, 2012 at 4:46

3 Answers 3


(See Semivowels in English and When is Y a vowel? for relevant info)

The sounds represented by the letter 'w' in English spelling are somewhat intermediate between consonants and vowels. Sometimes it is closer to a consonant (namely a semivowel or glide because even though 'w' doesn't result in a substantive occlusion in the airstream, there is a restriction of airflow as with the similar glide y. This occurs when the sound (with corresponding letter) appears at the beginning or middle of a word or syllable.

But the letter can also represent a sound that is closer to a vowel when it is part of a diphthong (a double vowel or a vowel followed by a glide, like in the word 'brown').

Which is all to say that the dichotomy of consonant/vowel, while very useful, does not capture the entire complexity of articulation; there are more overlapping categories between a stop (like 'p') and a pure vowel (like 'a').

As to 'cwm', it is a borrowing like the 'll' in 'Lloyd' that represents a non-native (to English) sound and the non-native spelling.

So to summarize for you explicit questions:

  • 'w' in 'cow' is a glide (which is considered a consonant (but a sonorant which is closer to a vowel))
  • yes, it is the same as in 'how'.
  • if 'w' is vowel-like, 'y' is similarly vowel-like.
  • a vowel is a sound produced by "no build-up of air pressure at any point above the glottis".
  • 2
    Er, I'm pretty sure that the w in cwm just represents [u] in Welsh, which is a sound that's also present in English. The spelling is the only thing different about it. May 16, 2011 at 1:11
  • @JSBangs: to be frank, I wouldn't have a clue as to how vowels sound in Welsh, so I said it that way to be technically correct without actually knowing.
    – Mitch
    May 16, 2011 at 1:27

The original rhyme went like so:

A, e, i, o, and u — and sometimes y and w.

It helped students memorize the five vowels and the two dependents. The original Greek also had five vowels and two dependents: α (alpha), ε (epsilon) and η (eta), ι (iota), ο (omicron) and ω (omega), and υ (upsilon) — here listed out of chronological order in the Greek alphabet to show the similarity with the English rhyme.

W is also a vowel in words like fallow, mellow, and hollow where it is silent, similar to the e in tube. And, of course, that rule follows for the y in turkey, monkey, and their ilk.

I don't have any research per se; I'm just really old and remember my elementary teachers. Sadly, you're right, students aren't taught anymore where their language came from and why grammar or spelling rules exist.

Hope that helps.


It's a diphthong.

A diphthong is two vowel sounds in one syllable. The diphthong ow and ou make the ow sound as in cow.


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