1 in 10 children have a speech or language difficulty.
Most children have their first word by the time they are 12 months old.
Many children can combine words into 2-word phrases by the time they are 18 months to 2 years of age.
5% of children stutter, but only 1% continue to stutter into adulthood.
A chimpanzee named Koko has a vocabulary of 500 words she can speak using American Sign Language. The average English-speaker has a 20,000 word vocabulary.