Toddlers, while one of the more charming and adorable times in human development, but also one of the most challenging for parents, marked by significant developmental milestones. Toddlers are defined as any child between the ages of one and three. Toddler development during this time includes great strides in physical size, gross and fine motor skills, speech, and socialization.
At one year of age, a neuro-typical child should be able to display most, if not all of several important skills, including being able to pull themselves up to a standing position, be able to sit without assistance, respond to his or her name, and be able to say short words such as "mama," and "dada." By the age of two, a child has about a dozen of their baby teeth, with the full set arriving by the age of two and a half.
Toddler development proceeds so that by the age of two, the child has a vocabulary of approximately 350 words, the most frequently used of which is "no." Toddlers at this age also, while being able to begin to dress themselves, see every possession as their own. The "this is mine" phase is a foundation of the stereotypical Terrible Twos. Major social milestones in toddler development generally include successful toilet training, and being able to parallel play. The final stages in toddler development sees the child displaying preferences, and understanding the differences between boys and girls.