Vocabulary development during the preschool years is related to later reading skills and school success in general. Use gestures and facial expressions to help children make sense of new words. For example, when introducing the word joyful, you might smile and wave your arms about to convey what it means. Sing with children and recite poetry and rhymes to playfully introduce vocabulary.
From The Word Gap: The Early Years Make the Difference by Laura J. Colker