>>It all sounds like you're trying to say "I've got a duck egg in my mouth" but can't say it because you've got a duck egg in your mouth!
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>One of the books I used when I was learning English, written some time in 1930s by one mr. Vukadinović, who was a London correspondent for Politika, had this in the preamble:
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> ...and you may hear sometimes that the proper way to learn how to pronounce the English language is to practice in front of a mirror with a hot potato in your mouth. That is completely unnecessary, though I have heard of a few cases when it helped.

We often talk of posh people speaking as if they have a "plum in the mouth" or "with a plummy accent"

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>And a little later, on the same subject:
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> Two of my colleagues, both longtime journalists in London, had quarelled about the proper way to pronounce "such" - one said it was to be pronounced s-ah-ch, the other s-aw-ch. They decided to solve it with a simple test. They wrote the word on a piece of paper, and asked the first gentleman on the street to read it aloud. Once they heard the proper pronunciation, they simultaneously turned to each other with "What did I say?"
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Where I come from, it would be "sooch" as in "soot"