This factor may be due to the characteristic facial abnormalities and relatively large tongues of Down-syndrome children.
Nevertheless, Down-syndrome children often are very sociable and interested in conversational language.
The extra chromosome in Down syndrome is labeled number 21.
As people with Down syndrome age, they face an increased chance of developing the brain disease called Alzheimer's (sometimes referred to dementia or senility).
The Down syndrome adolescent with an IQ of around 50 points does not seem to progress beyond the grammatical level of the normally intelligent child at three years, with short sentences that are restricted in variety and complexity.