This document outlines the intellectual development of toddlers between 12-24 months. During this period, toddlers begin discovering new ways to solve problems, repeating actions to achieve goals, and forming one word sentences. Between 18-24 months, toddlers develop deferred imitation where they can recall and imitate observed behaviors later. They also begin thinking about goals and hiding games. Their language develops to include 2 or more words in sentences and they may substitute, drop, or change letters in words. Parents should talk with their toddler correctly without correcting to support the fastest vocabulary growth around 30 months of age.