limited ability or even inability to comprehend or formulate language because of damage to specific brain regions (cerbral vascular accident, head trauma etc.)
an absence of speech while conserving or maintaining the ability to understand the speech of others. Mutism is typically understood as an inability to speak on the part of a child or an adult due to an observed lack of speech from the point of view of others who know them such as family members, caregivers, teachers, etc.
cluttering (a speech and fluency disorder characterized primarily by a rapid rate of speech, which makes speech difficult to understand) and stuttering (a speech disorder in which the flow of speech is disrupted by involuntary repetitions and prolongations of sounds, syllables, words or phrases as well as involuntary silent pauses or blocks in which the person who stutters is unable to produce sounds)
