For a while, my daughter said “Bubba” instead of Grandpa. Incidentally, Grandpa looks a bit like Bill Clinton. I have a great video of her pointing at a picture of Clinton on my laptop and saying “Bubba!” repeatedly.
Does it count if it’s the wrong way around? My mother used to say there was a draft coming from the cupboard (it was a big old drafty walk-in type thing). Somehow my sister became terrified of going in the cupboard. Turned out she was frightened of the giraffe that supposedly lived in the cupboard. So now we still say “someone shut the window before the giraffe comes in”.
Double-decker busses she called “bunk-bed busses”. Starters (before main course) she called “fast-forwards”. I still think it makes perfect sense 
Same here, but I actually thought this was the name of the condition until I was 13 or so.
Makes sense, right? Only old people get it, right?
My daughter: Dinosaurs = Dinosaters
Daquiri = Dackleberry
My niece: red headed woodpecker = red hooded peckerhead
When I was little, vegetables were “venchtables.”
My little sister called birds “boodies” (rhymes with woody). She called their droppings boodie toodies.
My son used to express his agreement by saying “absoloopy” so, of course, we all still say it and he is mortified.
Driving by a BK as kids, my sister “Fa-gi-tas” (fajitas) and “cukes” was pronounced with a q sound. (it was a farmstand selling cucumbers).
I used to call fruit cocktail, ‘fruit tail cocktail’.
My daughter called the radio the ‘raidy roady’.
No idea what I may have said. My youngest boy always put an extraneous ‘n’ after every ‘s’ for awhile, i.e., ‘snausage’, ‘snoup’, etc.
When I was a kid, Pez dispensers were always called Pezlers. I still think that’s the proper name.
I still use the pronunciation un-dout-eb-ly. And “Andy GRITH-if.”
As a kid, I pronounced the name of the Greek philosopher “SO-crates,” in two syllables, the second syllable rhyming with “dates.”
I also mispronounced “Fitzgerald” as “FITZ-er-glad.” And “psychiatrist” as “phy-sha-TERR-i-ast.”
My younger sister used to rag me about my pronunciations like “pre-JOO-diced” and “by-GAMM-ist,” but she came up with “SOU-ther-un yams,” MAS-kus" (for “masks”),“PER-se-phone” (instead of “Per-SEFF-e-ne”) and “Pius Eks” instead of “Pius the Tenth.”
My now 16-y-o son gets very annoyed with me when I refer to “poop-taste,” which is how he pronounced toothpaste when he was little.
[QUOTE=Dragwyr]
My brother used to call “Salt and Pepper”, “Salten Pepper”, and used to say, “Please pass the salten”.
[/QUOTE]
This one made me laugh out loud. Adorable!! “Please pass the salten.” 
[QUOTE=rachelellogram]
The only one I can remember doing is the alphabet song. At the “L M N O P” part, I would say “menno menno p.”
[/quote]
Ha! I would say “emenemopee”
My nephew:
strawberries = strawbellies
clouds = plouds
My twin brother and I both pronounced our "r"s as "w"s, which made for all kinds of cutesy little mixups I’m sure. One of my favorites was my brother saying “dump twuck” - cutest thing ever.
My little sister once said “Henry Ville” for Henry the 8th (VIII).
I always called my grandmother “How” or “Howie”. According to my mom, this started because my parents tell my toddler self “We are going to Grandmother’s house” and I would say “Go see How!” They used the long term Grandmother because Howie did not like any such names as Gram or Granny. And my sister and I would always call my grandfather “Grandfeather”.
Afijstan.*
Rekyjavik.*
Hunson River.
Fugs Bunny.
(*with normal English “j” sound.)
The first two were from reading an atlas (obsessively).
I used to pronounce the video game “Deus Ex” as “Day o’ Sex”…wait, that’s how it is pronounced.
Ludovic, that sounds like the out-of-town friend of a man named Sexauer (there are such people!) who phone the guy’s workplace and asks: Do you have a Sexauer there?" and the person answering says, “we don’t even get a coffee break!” 
Both of my kids talked early and fairly well. My son did have trouble with Rs and Ls, and there were lots of cute instances there (to this day when we hear the Presidents of the United States “Lump” we all break out into “wump sat awone in a boggy mawsh…totawwee confusing aww the passing paWAnnas!”), but my daughter didn’t mispronounce much of anything. There’s only one word I can think of and it’s a family joke to this day, it’s the word “eggrock”. When she was around two, she would ask “is it eggrock”? It took us quite a while to figure out what “eggrock” was. We grab toys, or point at things and says “is this an eggrock, is THIS an eggrock”?.
And it would always be “no, no…no”. The best I can remember how we finally found out is that one evening I was getting her ready for bed and she said “it’s time for bed, it must be eggrock”. And the light bulb went on…OOooooOOOH, Eight O’Clock/Eggrock, OOOH".
She’s the one who also once asked (at 3 or 4) are you going to give the pizza bones (crusts) to Brodi? (the dog) So pizza bones they are, to this day. She’s 32 now and the Wump kid is 20 and pronounces his r’s and l’s just fine.
(forgot to add). My little sister called chicken and dumplings - chicken and dunklings, which really makes a lot more sense as they are dunked into the soup.