A toddler is a young child who is of the age of learning to walk, between infancy and childhood. Toddling usually begins between the ages of 3 and 6 years. Glossary, A place of our own During the toddler stage, the child also learns a great deal about social roles, develops motor skills, and first starts to use language. Toddler (1-3 years old) Physiologic changes Abdominal breathing, RR slows HR slows further 110-90 per minute BP increases 99/64 mmHg Brain develops to 90% of its adult size Mid… (More on Toddlers)