"Marble mouth" is a slang or idiomatic term used to describe a speech impediment where someone's speech sounds mumbled, garbled, or difficult to understand as if they had "marbles in their mouth." This expression is commonly used to characterize unclear or indistinct speaking. Additionally, there is a practice linked to this expression where people put marbles in their mouth while reading aloud to help improve their enunciation and slow down their speech. This exercise forces the speaker to focus on the mechanics of speaking, thus helping to reduce stuttering, mumbling, and filler sounds like "uh" or "like." In short, "marble mouth" means speaking in a muffled, unclear way, and it can also refer to a method used to improve speech clarity by simulating the difficulty of having marbles in one's mouth to encourage clearer pronunciation. This term can relate to mild speech impediments or challenges in articulation. The phrase is rooted in the idea that having actual marbles in your mouth forces you to speak more deliberately and clearly, thus breaking old speech habits that cause mumbling or stuttering. So, if someone says you sound like you have a "marble mouth" or "marbles in your mouth," it means you're speaking unclearly or mumbling.
