To answer your question, which is definitely not "stoopid", nearly 400 million native English speakers in the US and Canada. In American accent, we pronounce the tense U without the yod (IPA /j/, the sound of the English Y) when preceded by a coronal consonant in accented syllables. There are a few exceptions, where the yod has coalesced with the consonant, for example: mature, sure. In some accents, this yod-dropping may be more extreme than in others, but there’s really no reason for an American to ever use the spelling “stoopid”, as it really sounds the same as “stupid” in American English.

Hi Nicola, Very Simple Answer; You will hear "stoopid" used by North Americans and the "stupid" pronunciation used by Britain and everyone else ;) It will apply to other other similar words with similar spelling eg tumeric or cupid. The stoopid prounciation is how very young children talk so unless you are living in the USA best pronounce "stupid" or they might think you are infact .... the aformentioned. No more thought required. BONUS: Also Americans use the same sound to pronounce words like " dew " like "dooo" intead of "dew" ! like "djew"

Thank you for your comments, everyone. "Double-o stoopid", that is hilarious, Jessica. I assumed there was a special pronunciation reflecting the exaggerated spelling but turns out there isn't and it's just a BrE vs AmE difference. That's one way of making oneself look stoo... never mind. Good point, Chris. I heard it as /stu:pɪd/ and to my ear, which had been exposed mainly to British English, it sounded unusual.

Hello Nikola! I'm originally from New Jersey and I pronounce it like "stoopid". It is definitely a regional thing (NY, NJ, PA). When I use that word in a joke I'll make the "oo" sound more pronounced. I might say something like "what are ya STOOpid?!?" (This is slang and a joke). People often do self-deprecating humor in New York/New Jersey as well. Overly pronouncing "STOOpid" can be used in this way. We'll say something like (Ugh I forgot my book at home. I'm so STOOpid!). Teenagers say those kinds of self-deprecating jokes a lot. For the Frank Sinatra song- it may have just worked better with the song. Sometimes singers will overly pronounce a vowel during a song just because it sounds nice. From the Sinatra songs I know, I can't remember him using that word in a very meaningful way. What song was it? I hope I answered your question! If you have any other questions I don't mind answering.

What difference are you trying to present? A different vowel? A different stress? The standard pronunciation is as follows: stupid [ BrE ˈstjuːpɪd, AmE ˈst(j)upəd ] With phonetic spelling, a child would start with "stoopid" and then learn that the standard spelling is "stupid."