It may start with a simple word you can't pronounce. Your tongue and lips stumble, and gibberish comes out. Misspeaking might draw a chuckle from family and friends. But, then, it keeps happening. Progressively, more and more speech is lost. Some patients eventually become mute from primary progressive apraxia of speech, a disorder related to degenerative neurologic disease.

Source: Speech disorder called apraxia can progress to neurodegenerative disease