You asked

When will my baby understand no?

Some babies will start to understand what no means at around 6 months of age, but most won't stop what they're doing until they reach an age between 12 and 18 months. Even as they get a little older, they still will have a very short memory. For babies, once something has happened, it's over. They don't remember that it was just yesterday when you told them not to do a something.

It's second nature for babies to be curious. They do most of their exploring by touch and can't resist touching anything within reach. Baby proofing your home is a good way to prevent accidents in their early exploring days. If you think that you are using the word no too frequently, try using words that why they shouldn't be doing what they're doing. For example, when they reach for the dog food bowl, you could say “Yucky”. Or if they get too close to the oven, say “hot”. The tone of voice that you use should convey the meaning of your message.

Keep in mind:
•    You can never spoil a baby, when they cry they require your immediate attention.
•    Babies are not naughty and doing things on purpose to upset you.
•    Babies under one year of age have very short memories.
•    The best way of stopping a baby from what they doing is to quickly distract them and divert them to another activity.
•    Actions speak louder than words. The act of distraction works much better than shouting or smacking.

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