Stammer

Part of speech: noun (n.)

Defective utterance, or involuntary interruption of utterance; a stutter.

Part of speech: verb (v.)

To make involuntary stops in uttering syllables or words; to hesitate or falter in speaking; to speak with stops and diffivulty; to stutter. I would thou couldst stammer, that thou mightest pour this conclead man out of thy mouth, as wine comes out of a narrow-mouthed bottle, either too much at once, or none at all. Shak.

Part of speech: verb (v.)

To utter or pronounce with hesitation or imperfectly; -- sometimes with out.