A person who talks like they have a mouth full of marbles
Wonder what Marble Mouth is going to try and say?
by unstable bob June 30, 2017
Get the Marble Mouth mug.
"Marble Mouth" is a slang term used to signify people who possess a slight speech impediment. It's hard to describe, but it certainly has nothing to do with location or cultural background like one definition ridiculously stated. It's not that they stutter - they don't necessary. But it's obvious that speaking is not their strong suit and they sound as if they have a mouth full of marbles. Marble mouths, more than anything, are highly annoying because you just want them to spit the words out already.
Eli Manning. A perfect example of a marble mouth.

"Just waanted to go dowanfield and duhduh get the win."
by Stormvessel June 23, 2015
Get the Marble mouth mug.