At 15 months, toddlers experience significant physical, motor, and cognitive development. They can walk without support and climb stairs, though balance is still developing. Fine motor skills like building towers and scribbling emerge. Communication skills grow as toddlers understand more words and say short phrases. Play becomes more complex as toddlers engage in pretend play and interactive games with caregivers. Providing toys that encourage physical activity, cause and effect, and pretend play can further stimulate development at this stage.