The same way as you get /gloster/ from “Gloucester” and /wooster/ from “Worcester” – and /wensday/ from “Wednesday” – i.e., by dropping an unstressed syllable.
Actually Wooster is a different city, I think, than Worcester. and I’ve usually heard the latter referred to as “Worster”. And I don’t agree with those pronunciations either.
Leicester seems to be more eggregious than most, or did I dream it?
There’s a town in Ohio called Wooster, pronounced the same way as the English city Worcester. And Leicester is definitely pronounced /lester/ – my mother came from that city, and I’ve been there many times.
I’m sure your brain thought “cue” but your fingers typed “queue.”
Hail Linguists!
Which is an example of exactly why talking about letters, instead of sounds, confuses things:
H is a not a vowel, but: an honor, an herb, etc.
On the other hand: a honk, a hermit, etc.
Or should we just call H a semi-vowel too? :smack:
However, there are a few situations when talking about letters is the primary teaching tool, namely, with certain rules of orthography. E.g., when to double a consonant letter before -ing:
*wait* => *waiting*
Whereas:
*cut* => *cutting*
This has nothing to do with phonetics (though it does, at times, have to do with stress).
Then again: die (“to cease to live”) => dying
While: die (“to impress, shape” etc.) => dieing
By the same token: An umbrella, but a unicorn, since “unicorn” is pronounced “yooneekorn”.
Well, in Britain I hear there exist the last names:
Marjoribanks: /Marchbanks/
Cholmondeley: /Chumley/
Featherstonehaugh: /Fanshaw/
Assuming you’re talking about the same Worcester as the rest of us (ie the original one 
), it’s definitely ‘Wooster’.
If you’re talking about the city itself, then maybe, yes…
Don’t forget St John, which featured in Four Weddings…
Worcester Massachusetts is WIS-ter. I don’t know why.
At the risk of taking this even further OT, there’s a village in Cornwall called “Mousehole” which is pronounced “mouzle”. 
What about were, where, why, etc.? Are these examples of dipthongs? If so, the same part of the dipthong in how?
Also: English spelling often uses a single letter to represent a dipthong–this might be because English dipthongs are pronounced in such a compressed manner. Example: I = /ai/.
I agree with bordelond that, with letters (and sounds), the distinction between “vowel” and “consonant” can be quite blurred. I maintain that the reason for a teacher to assign these terms can serve only to help with a few spelling rules, and I’d bet that few of even the best copy editors could actually tell you what those rules are–they just “know” them from reading a lot. Grade school teachers talk about vowel letters and consonant letters mostly because that’s what they think they’re supposed to teach.
Ah, good point. I’ve been studying about message queues lately, so my fevered brain is somewhat obsessed. Still, I like your idea of blaming it on my fingers.
Meanwhile, no etmiller, I don’t think the “w” in were or where is part of a diphthong. It seems to me that it’s acting as a consonant there. That’s different from how it acts in “how”. If it were spelled “hou” or “hao”, we would call “ou” or “ao” diphthongs.
I’m still not clear, why do we usually hear “sometimes Y”, but rarely “sometimes W”?
From English Grammar in Familiar Lectures, which dates from 1828, and is available from Project Gutenberg,
So the “W is sometimes a vowel” idea has been around a long time. I, too, would be interested in whether it was always hit-or-miss whether W was included along with Y, or if it always used to be included, but got dropped along the way for some reason.
I like the breakdown of the consonants into mutes, semi-vowels, and liquids in the quote above. To this non-linguist, that makes a lot of sense.
I notice that that quote does not classify h, j, or q, and I would debate x and soft g’s status as semi-vowels. Of course, they completely avoid the question of the difference between perfect and imperfect sounding… I fail to see how “eeee” is more perfect than “ssss”. And most English speakers find it easier to unite “s” with other consonants than they do “m”, which also casts doubt on their definition or examples of the liquids.
Needless to say, that particular link really can’t be considered authoritative anymore.