relaxed pronunciation in writing?

There's even a phoneme-free way of expressing "I don't know" just by using tones.

I feel like it may have been popularised by The Simpsons.

Say "I dunno" with a rising inflection. Then pronounce those three tones as though they were mud: "ur-ee-ur".

Does anyone know what on earth I'm talking about? Or have a better way of expressing this?

A friend of mine told me that there's a Spanish curse phrase that can be whistled. Apparently it's a way Spanish speakers can insult foreigners without their knowledge. The tone of the whistle sounds rather like the way this rude phrase is pronounced. Any info or clarification on this?

In the movie MAS*H (not the series), the character Hawkeye uses a distinctive whistle towards an officer he does not respect. I suspect it might be this Spanish whistle insult. Or maybe not. It also sounds a lot like the whistle Harpo Marx (the silent one) used to communicate with his brothers. Also three tones.

I think the scene I'm thinking of is from A Day at the Races.

Harpo: 3-tone whistle
Chico: Doctor hackin a bush..
Harpo: (mimes a portrait picture)
Chico: Is being framed ...
Harpo: 3-tone-whistle (plus tracing exaggerated curves in the air)
Chico: By a woman!

etc

Does anyone know what on earth I'm talking about?

Not really, but you remind me of a story. A friend of mine was visiting his grandmother, non entirely compose mentis, in a nursing home. The staff in the nursing home said that she kept mentioning someone called "Lionel" and asked if he knew who that might be. He doubted that she even knew the name Lionel, much less anyone who went by that.

When he heard her speaking in her own mix of English, Sicilian, and Italian, he realized that what the staff heard as Lionel was her pronunciation of "I don't know" in sort of the way you describe. Ay uh nuh.

(He has also told me that even in her compos days she used to exclaim Guffooneseks!, which is what she made of "For goodness' sakes!")

Count - it's more like uh-uh-uh or mm-mm-mm in 3 distinct syllables with a kind of a sing-songy tone to it.

Does anyone know what on earth I'm talking about?

Of course. My kids have only just emeged from their teens.

In Scotland, there is also "gonny" as in gonny no or "ah'm gonny kick yir heid in pal"

One way to hear it is to say "I don't know." Then say just the vowels in the same tone "I oh oh." Then say "mm mm mm" in the same tone.

I helps if you also throw up your hands in in an "I don't know" gestrue.

OK, from sasha's description I know what the Count is talking about.

There's even a phoneme-free way of expressing "I don't know" just by using tones.

I feel like it may have been popularised by The Simpsons.

I feel morally certain Scooby Doo got there first.

Of course. My kids have only just emeged from their teens.

Oh, you mean the neanderthal grunting stage? (waiting patiently for a SiT poster to tell me testily that the neanderthals had a rich and complex form of verbal communication far in advance of the modern teenager)

OK, from sasha's description I know what the Count is talking about.

Jolly good. Have you seen the latest Spongebob Squarepants movie yet? That can remove all doubt.

http://www.wisevid.com/play?v=1tbvdAxct-wb

At the 18 minute mark, during a game of bad mitten:

Spongebob: Patrick, do you remember how to play this game?
Patrick: mm-mm-mm.

My 9-year son old does that "I don't know" with tones. One of many attributes he shares with Bart Simpson.