New York, June 21 -- If you want your child to have a rich and fulfilling life, one of the best things you can do is help build your child's vocabulary. Research shows strong language ability is associated with a number of positive things, including happiness, friendships, connections with family, academic success and a satisfying career.

Building your child's language ability is not something you should wait to do until they're old enough to go to school. Vocabulary development is extremely rapid. Between birth and second grade, children, on average, learn about 5,200 root words.

The ability to quickly interpret words at 18 months can determine the size of a child's vocabulary later in childhood.

By grades three and four, vocabulary a...