Why is the letter Z associated with sleep?

[friggeri]

http://www.straightdope.com/columns/read/3063/why-is-the-letter-z-associated-with-sleep

[swores]

"you know what they call sleeping in the UK? Catching some zeds."

We do? Literally never heard that, not a single time.

As to the fact that it comes from snoring... am I the only one who thought it was obvious as soon as I read the title?

[bitdiffusion → swores]

Not a word, exactly, but certainly a variation of http://en.wikipedia.org/wiki/Onomatopoeia

[hnriot → bitdiffusion]

z in the US is pronounced zee, in the UK zed, so certainly not an example of onomatopoeia for Brits, or a particularly good example for Americans. It's certainly a stretch to attribute it this way.

[swores → hnriot]

I don't know about in American, but in the UK it's not that "zed" is onomatopoeic, it's "zzz" which is just the sound a z makes in a word, not "zedzedzed" or "zeezeezee". And that's why it comes from snoring.

[Peroni]

Here's a more pertinent question:

Why is this on the front page?