Wrong and utterly stupid pronunciations...

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I've also heard asparagus called"sparrows arse"

As a small not DH was very disappointed when the long awaited 'boating day' came along and instead of heading out to sea he found they were heading for the polling station.

This isn't, strictly speaking a pronunciation thing, but my Dad was always very impressed when he was a wee boy reading about the battalions of the British army. He had really thought they were "battle lions" ie big fighting cats which he thought was a great idea. He was very disappointed to find out the truth.

At 4 after a few days at a convent school I asked my parents why I had to pray to an "old nighty"

My daughter used Bunnystairs instead of bannisters. I find myself still using it.
My son used aminals. which is not an unusual consonant shift.

Names are always difficult, if you have not heard them before you might be forgiven. There was a child I knew whose name was written as Sian. Instead of the usual Welsh sounding "Sharn" she pronounced it as "See-ann."
Very difficult for anyone to get right.

Mama was from Holland and when the weather dude reported "scattered showers" she invariably earned us "shattered showers today!"

If someone would send me a box of victorious I would be very happy!

For years I wondered when little, why on earth a green hill far away would have had a city wall around it in the first place. I wish someone had explained to me what the alternative meaning of without was. A bit off-topic I know, but all errors are due to lack of communication somewhere along the line.

My mother was brought up in a grocer's shop and when she was a little girl she used to think that the reference in the national anthem to "victorious" was to "Victorias" (Victoria plums).

My mother always pronounced immoral as immortal.As in ''she was keeping an immortal house'' when someone in her neighbourhood was found guilty of running a brothel.
I remember when I was a pupil midwife a patient who came in to have her labour induced referred to having her baby seduced.She really thought that was the correct pronunciation.

Dad always ate chish n fips and pointed out flutterbys. We wore gubbies to keep our hands warm in winter.
Antiques are known to DH and I as anti-queues and DH is very partial to a slice of gatox and we both like bogonase, it's a family thing

I've just remembered my grandfather used to say horse piddle for hospital.

I seem to remember a really old black and white film about either a WW2 airbase, or submarine (take your pick) in which a character bounded into the mess room saying "I say! snorkers! Good oh!" the snorkers in question (now, that's a silly phrase, isn't it? After all the debated item was never "in question" in the relative sense. Note to self: go to bed you daft bat were sausages.

And he definitely did "bound" in the way that those sort of characters in that sort of film did.

A bit like the "anyone for tennis?" thing.

I'm going now.

Perscription and sustificate for prescription and certificate. Chimberley for chimney, I wonder if it's a southern thing.

I have heard many of my fellow Scots saying 'sangwidges' for 'sandwiches'. If it had been just one person's usage, I could have understood it as a personal eccentricity but it seemed to be prevalent in the West of Scotland in my youth.

NQers are a bit different (whispers it very quietly)

I have often heard of sausages referred to as snags. I just looked through the list and some words I have never heard of. Different states do use some different words such as South Australians say fritz and other states say luncheon meat for cold slices of meat.

My DN used to say 'viggener' for vinegar so it is often referred to as that in our family.
Penguins are always pegawings (DN) or pengits (DD). Envelopes are 'envelblokes (DD again).
We do know how to pronounce these words, but other people may not realise and think we are very odd or, as the OP, utterly stupid!

Tonight as I was returning DGSs 1 & 2 to my DD1 the little one ( 2yrs 3mths) spotted a Virgin Hot Air Balloon and shouted excitedly to his mum 'look, look a 'ot air laboon!'

Well, never heard them refer to a sausage as a snag myself (always a sausage, never a banger which seems peculiarly British).

Perhaps South Australians are different from North Queenslanders! Or North Queenslanders are different!!

No one understood? I'm very surprised!

That's a well-known Americanism, like nucular and aloominum!

I have never heard anyone say sanger for a sandwich. They would either say sanger and bread for a sausage wrapped in bread or sangers and mash, the sanger referring to the sausage. Most people I know would normally say sausage anyway.

I've said it before, but no one understood! I HATE the way Americans refer to a scientific study area (which on my planet is called a "laboratory") as a Labratory!!! They miss out the "o" between the "B" and the "R" !

Gems from our 2 year old GS: cappertillar, swy flotter, birdylade.

I knew someone who used to call mange touts "mangle towts" - it was a genuine error and not an affectation.

I also know someone who mistakenly calls Mozilla Firefox "Mozarella Firebox." It is hard to keep a straight face!

en.wiktionary.org/wiki/Appendix:Australian_English_terms_for_food_and_drink

Someone who was given a Gukki handbag (obviously Gucci), politicians who crate instead of create and anenomies instead of anemonies. My youngest GD aged 3 couldn't say a 'j' and always said plum dam. I asked her if she would like some plum dam on her toast, she looked me in the eye and said "you're not saying it right". I suppose it isn't fair to smile, if you haven't heard how a word is properly pronounced, how would you know?