Why Toddlers' Vocabulary Grows Quickly

McMurray considered the 2,000 most frequently spoken words of the English language. The list includes easy words and more challenging ones.
McMurray theorizes that there's a tipping point at which children's vocabulary typically takes off.

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"They have to be learning more than one word at a time, and they must be learning a greater number of difficult or moderate words than easy ones," McMurray explains. "Using computer simulations and a mathematical analysis, I found that if those two conditions are true, you always get a vocabulary explosion."