Vocabulary is commonly defined as "all the words known and used by a particular person". Knowing a word, however, is not as simple as merely being able to recognize or use it. There are several aspects of word knowledge that are used to measure word knowledge.
A robust vocabulary improves all areas of communication — listening, speaking, reading and writing. Vocabulary is critical to a child\'s success for these reasons: Vocabulary growth is directly related to school achievement. The size of a child\'s vocabulary in kindergarten predicts the ability to learn to read.