This is genuinely fascinating. Thanks to Multilingual Mama for bringing this to my attention!
Originally posted on Multilingual Mama:
Prisecolinensinenciousol, a parody by Adriano Celentano for the Italian TV programme Mileluci is sung entirely in gibberish designed to sound like American English.
Confession: having not read the description when I first watched this, I spent ages trying to figure out what he was saying. D’oh.