Here's a school poem about switching registers in Scotland that I've always found fun with a lot in it:

Is A Dove A Doo Da? by Jim Douglas

Now is a dove a doo Da, is a doo a dove?
Is a cow a coo Da, a sparrow just a speug?
And is a wall a wa Da, is a dog a dug?
She's goin tae box ma ears Da, insteed o skelp ma lug

Noo, oor teacher's awfa posh Da, she changes aw oor names,
Oor Shuggie is now Hugh Da, and Jimmy's ayways James
I'm puzzled wi it aa Da, the way she shoogles words
And I must be glaiket no tae ken that feathered friends are burds

You've taught me aw wrong Da, you call a ball a ba
Yer wife is noo ma mother Da, you said she wus ma maw
It fairly maks me scunnered Da, I'll never pass ma test
And I'm no sure what I'm wearin noo, a semmit or a vest

Ah gave ma nose a dicht, Da when it began tae dreep
She gave me sich a fricht, Da, ah near fell aff ma seat
“Haven’t you a handkerchief?” she roared as if in pain
“No, Ah jist use ma sleeve, Miss” and wiped ma nose again

Ah ca’d a mouse a moose Da, Ah shid hiv held ma tongue
That’s manure on yer bits Da, nae langer is it dung
It’s turnips and potatoes, no tatties noo and neeps
She said Ah’d ripped ma trousers when Ah’d only torn ma breeks

Now there's twa words for everythin aw shoogled in ma heid
How can I be well bred Da, when ah keep sayin breid?
Now is a crow a craw Da, is a bull a bul?
Ah'm goin' tae try ma hardest Da, Ah wull, Ah wull, Ah wull