An innate ability for language acquisition is the claim that humans are genetically pre-programmed to learn language. Observations such as the uniqueness of the human speech organs, the speed of acquisition of language, the presence of linguistic universals, and the claim that language is unique to humans are all used to support this view.
There are many stuttering problems for people who stutter. People with an established stutter are aware of the negative effect of repetitions, prolongations, hesitations and blocks on their speech. Their stutter (stammer) may be accompanied by facial tics and uncontrolled body movements. Stuttering can lead to the avoidance of certain activities and to social isolation.