Remember the game of 'telephone' you played as a kid, where you whisper something to someone, and they whisper it to someone else, and by the time you get to the end of the circle it's unrecognizable? Talking to a 3-year-old is like that, except they're the whole rest of the circle.
There are different variations on the theme. Some are just inability to pronounce things (pasketti [spaghetti], chawt-lick [chocolate], etc.) Another is replacement of one phrase with another that sounds similar, but is comically incorrect. Mind you, this happens with all of us--like mis-hearing Jimi Hendrix's "'Scuse me, while I kiss the sky!" as "'Scuse me, while I kiss this guy!" and so on (another friend of ours misinterpreted the Ramones' "I wanna be sedated" as "I wanna piece of danish" for years, with encouragement from her older siblings).
Alana has several of these that we enjoy:
Her friend, Tommy, has a bit of an obsession with trucks; construction trucks, big rigs, you name it. The other day, we were getting out of our car and Alana points to the pick-up truck next to ours and says, "Look, it's a mustard truck!"
Hunh?
She says, "Just like Tommy's mustard truck!"
After wracking our brains, we finally realize that she's saying 'monster truck'. *LOL*
She also has a "barbeque doll" (you've all seen these...statuesque figure with narrow waist, boyfriend Ken, etc.)
And, finally, when we're all in the mood for french fries she asks if we can go to "Old McDonald's".