Children who have studied sign language have higher IQ.

Baby sign language was established by American child development education experts as early as 1982. The American Health Association has also conducted research showing that babies who have learned sign language can speak like 27 to 28-month-old babies when they are 24 months old; their language skills at 36 months are approximately one year ahead of their peers; and by the age of 8, their average IQ (intelligence quotient) will be about 12% higher than that of children of the same age.