<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> A toddler is a child 12 to 36 months old . The toddler years are a time of great cognitive, emotional and social development . The word is derived from "to toddle", which means to walk unsteadily, like a child of this age . </P> <Table> Normal vital parameters of toddlers <Tr> <Td> Blood Pressure (mmHg) </Td> <Td> Systolic </Td> <Td> 80--110 </Td> </Tr> <Tr> <Td> Diastolic </Td> <Td> 50--80 </Td> </Tr> <Tr> <Td_colspan="2"> Heart rate (BPM) </Td> <Td> 90--140 </Td> </Tr> <Tr> <Td_colspan="2"> Respiratory rate </Td> <Td> 20--40 </Td> </Tr> </Table>

When does a baby officially become a toddler