For the past month or so I’ve been increasingly bothered by the sometimes-vowel “Y.” And consequently, I’ve been bothering my husband about it. Specifically, I’ve wondered when is Y considered a vowel, and when is it not? And why? Shouldn’t it always be one or the other or always both?

I finally looked it up on Wikipedia. The reference link appears at bottom.

It turns out, there is a reason that no one cares to answer this. It’s a complex reason. Here follows my understanding of the Wikipedia-provided information. Note: to keep things “simple,” I’m only going to explain as it applies to English.

So, as you know, we have vowels and consonants. Further, in our spoken language, we have phonetic vowel and consonant sounds. The phonetic sound of a vowel is one in which the airway tract does not close, or there is no build-up of pressure. Contrast the way you say “aaah” and the way you say “shhh.” In the “aaah” noise, there is no build-up of pressure anywhere along the vocal tract (instead you just sort of push out the sound from your lungs). When you make the “shhh” sound, there is constriction or closure at some point on the vocal tract (when you make the noise, try to focus on your airway in your throat – you may feel the tightening). As you have probably figured out, the “shhh” noise is an example of a consonant. I’ll discuss consonants as they relate to vowels, but I’m not going to get too deeply into them.

That is one half of the definition of a vowel – the phonetic half.

The other half is the phonological definition. I’m taking phonological to mean, in this case, the sound system of English – that is, the system used to create syllables and meanings imparted therein. Phonetics is the means we use to mechanically produce these noises (I’m ignoring sign language; I apologize). So, phonology is the system of sounds that create words and the way we use those sounds, and phonetics is the sounds themselves.

Phonologically, vowels form the “peak” of a syllable. Consonants form the onsets and codas (for languages that have them).

As you may have already begun to deduce, sometimes the phonetic and phonological definitions clash. Wikipedia uses as examples the approximants [j] (y-sound, like in “yet”) and [w] (like in “wet”). An approximant is, most basically, a sound that is partway between a sound that produces a “turbulent airstream” (consonants) and a sound that creates no turbulence (vowels). I love that phrasing – turbulent airstream. Anyway, a [j]* is not exactly as effortless for us to produce as a regular vowel noise, but it is pretty close; it’s also not quite like a hard consonant noise. And, in the above example of [w], when you say “wet” out loud, you’re also not exactly producing a turbulent airstream until you get to the “t” glottal stop. Since they have minimal turbulence, they are like vowels (phonetics); however, since they appear at the beginning of a syllable, they are placed as consonants (phonology).

So the answer is that “Y” is an approximant – it sounds like a vowel but behaves like a consonant. My next question, I suppose, should be, why don’t we declare the vowels to be A, E, I, O, U and sometimes Y and W? A question for a later date.

http://en.wikipedia.org/wiki/Vowel

* note that when letters or marks are in brackets in phonetics, it’s a sound, not a letter as you and I might know it.