Fajitas is pronounced fuh-JITE-is.
From my son when he was a wee lad…the stuff one cleans one’s teeth with is pooptaste.
Rectum? Damn near killed 'im!
I always mispronounce “calibre” as “kah-LYE-ber” …sometimes people pick up on it, more often they don’t …I always wonder if they are asking themselves …" maybe that ***is ***the correct pronunciation " …
There was an episode of Sanford & Son where Fred called hors d’oeuvres “horse divers”. Lamont said something like “It’s French. It’s pronounced ‘hoors dee ovrays’.” So that’s how I say it.
I also say “Mucho garcia” for “Muchas gracias” and, with a heavy southern accent, “Oh contrayer, moan amee!”
Muchas gracias is Mucus Garcias.
There’s a NY bread company, Ecce Panis, which my dad called Icky Penis.
Horse Doovers was around in 1939, per this picture from San Francisco.
Charles Krauthammer is Charles Coathanger, because he frequently looks as though he’s left it in his suit jacket.
Well, there’s the entire French language, which I am most assuredly not fluent in, nor do I have even a passing familiarity with the rules of pronunciation of. I tend to pronounce it with a heavy hillbilly/southern accent, rather like Lt. Aldo Raines saying “BONE JORE NO!” in Ingluorious Basterds.
I also like “beacuase” from the “Dot Dot Dot” video, and “pengwine” / “Nelson Mandohla” from a certain Mongrels gag.
Thank you – I honestly never digested this. MISSchevus and not mis-chee-vee-ous for a reason!! This is right up there with when I realized I was saying comfterbuhl. :smack:
Very, very un-PC, but ever since seeing this comedy routine (when it originally aired on HBO in 1984), shoulder pads have been sholdamapads.
When we were kids, one of my little sisters curiously quizzed us as to why there was a bathroom, a bedroom, a livingroom, a diningroom, but we didn’t call it a kitchroom. Naturally, I’ve called it a kitchroom my whole life since then.
When Spiny Norman and I first got married, since he’d never heard it spoken and only read it in print, he pronounced the word “cabinet” as if it were French: cabinay. You know, like buffet? So of course our kitchroom is now full of cabinays. 
Wunderbob I call it a Bambilance too. An EMT friend got a frantic call once from a guy calling in to send teh “bambilance” cuz he just hit a deer.
I thought it was really pronounced “wers-deh-sheer” sauce … ? But I call it “werchestershire” just to annoy ppl.
And “cahmPORtable” means comfortable. We used to giggle at one of our English-as-a-second-language nursing instructors who would always ask our patients if they were “cahmPORtable” (checking up on us).
Medical industry is so ripe for mispronunciations and jokes about it, since so many non-English speaking interns are training in hospitals I work at. Examples:
“Oo get the Walium (Valium)! … He is in PeeWeeCee’s now(PVCs) … Ve’re in de major wessel (vessel) now”. Nurses are so unforgiving.
Muchas gracias is another one of mine, I say Much Grass instead. Similarly, I often say fangs instead of thanks.
The spouse and I say “mini fangs” for “many thanks.” Reminds us of kittens. We like kittens. 
I like to call Dutch people Hollish for humor reasons alone.
I also call it a FOY-yer on purpose too.
For some reason I can’t bring myself to pronounce croissant properly, I have to say it like a cretin and say cruh-SAWNT.
I also say JYE-ro just to irk people as well.
And the polite response to “Garcias” is… “de nalgas.”
I learned “horse doovers” from a Punch cartoon. I saw the cartoon in the mid '60s, but I think it dated from the '30s or '40s.
I say “Bum gerbils!” to mean Buon giorno - got that from an old Navy buddy.
And another Navy habit is to refer to the UAE port of Jebel Ali (near Dubai) as “Gerbil Alley.”
I pronounce typos according to their accidental spelling, Strong Bad style.
Beyonce and diabeetus.
Who is Wilford Brimley?
What did I win?
I say “Ja-la-pen-ohs.” Pronouncing the “J”.
Especially if they have consummate V’s.
Followup: Also, I give text-speak similar treatment. “Plz” becomes “pulzzzzzzzz”. The letter “u” subbed in for “you” becomes… well, imagine a gorilla going “Ooooo-ooooo-ooooo!”, but only one of them.