By the start of the preschool years at age 3 your little chatter box most likely understands 1,000 words. Beyond this, as the experts at PBS Parents note, preschoolers are learning roughly 1,500 to 2,000 new words between 3- and 4-years-old. While there's no precisely set list of vocab that your little learner has to master before she hits grade school, there are some words that preschoolers should know.
As your preschooler is building his emotional skills, he will need the words to adequately -- and appropriately -- express his feelings. Without emotion words to use, it's possible that your preschooler will resort to temper tantrums or aggression to express what's going on inside. Although these behaviors are perfectly normal for the emotionally unsophisticated preschooler, a full vocabulary that includes words such as angry, sad, happy, worried or mad can help your child to handle his emotions in a more effective way.
Your preschooler is now able sort and classify some objects. In order to do this she will need to know category words to fit other objects or items under. For example, she should know that the category "animals" is a broad heading that tigers, cats, dogs, elephants and giraffes fall under. Other useful category words are those that your preschooler may need for everyday life. In order to clean up at home your 3-year-old will need to know that the word "toys" is a general word that includes her dolls, trains or dress-up clothes.
Color words are part of a descriptive vocab that your child's preschool teacher, and later his kindergarten teacher, will expect him to know. Your preschooler should have the ability to look at a color or an object, recognize the shade and tell you the correct name. This isn't to say that he needs to name every one of the 300 crayon colors in the mega-box of hues, but he should at least know the basics. These include the primary colors of red, yellow and blue, the secondary colors of green, purple and orange and other basics such as white, black and pink.
It's unlikely that your 4-year-old will have the number vocabulary to count up to 500, but she should -- according to PBS Parents -- have the ability to recognize the numbers up to nine. By age 5 most preschoolers can also recognize and say number words up to 20. Knowing the correct names of the numbers is key for your child's ability to do math now and later on when she gets to kindergarten. Without a numerical vocabulary, your preschooler can't go on to do operations such as addition or subtraction when she gets to grade school.