When can children typically begin to understand and respond to discipline by saying "NO"?

At around 12 months of age, children typically begin to understand and respond to the concept of discipline, including the ability to say "NO." At this developmental stage, toddlers are becoming more aware of themselves and their actions, and they start to grasp the meaning of simple commands and expectations set by caregivers. This understanding is a key component of social and emotional development, as it demonstrates an emerging ability to differentiate between acceptable and unacceptable behaviors.

By this age, many children are vocalizing more, and the verbal expression of refusal, such as saying "NO," often emerges as they learn to assert their preferences and boundaries. This marks a significant shift in their communication skills, as they begin to engage more actively in their interactions with others. Overall, placing this milestone at 12 months aligns with the developmental expectations for social responsiveness and language acquisition in toddlers.