When can my baby undertand "NO"?

I think my son was a few months older when he knew what was hands off. I said no and pointed at the object/thing he wasn't supposed to touch or play with. It can be a royal pain, but you go to keep doing that, consistency is key. My grandparents told me to slap his hands, I didn't, here's a link why http://www.askdrsears.com/html/6/t062100.asp SLAPPING HANDS How tempting it is to slap those daring little hands! Many parents do it without thinking, but consider the consequences. Maria Montessori, one of the earliest opponents of slapping children's hands, believed that children's hands are tools for exploring, an extension of the child's natural curiosity. Slapping them sends a powerful negative message. Sensitive parents we have interviewed all agree that the hands should be off-limits for physical punishment. Research supports this idea. Psychologists studied a group of sixteen fourteen-month-olds playing with their mothers. When one group of toddlers tried to grab a forbidden object, they received a slap on the hand; the other group of toddlers did not receive physical punishment. In follow-up studies of these children seven months later, the punished babies were found to be less skilled at exploring their environment. Better to separate the child from the object or supervise his exploration and leave little hands unhurt.

Yes they can, you just have to train them to know what the workd "no" means. They will quickly learn that "no" means stop b/c what they are doing is not right or is displeasing to you. Putting things in her mouth though is normal and you will not be able to stop that.

At nine months I am guessing that your child is teething. When a baby is teething they will chew on anything they can get their hands onto. My suggestion to you is to get him something that he CAN chew on like a couple of teething rings. The kind you put in the fridge are good because the cold numbs the pain they are feeling in their gums. He is too young to understand no but you have the power to divert his attention by giving him something else to focus on.

Actualy at 9 months old no can be understood. they may not always remember what they can or can't do or touch but when you consistantly apply it, using voice tones and looks that show your displeasure, they quickly get the meaning. By a year old they fully understand what it means if youstart now. The key is consistancey and tone of voice.

I have a thirteen month old son, and although he understood the word no, he did not always react at that age. Around 12 months, the word no took a whole different meaning to him, and at thirteen months, he is perfectly aware of the meaning of no. I only use the word no very sparringly, because otherwise it ends up having no effect. Instead, he can tell in my tone of voice, or I will shake my head, and remove him from whatever he is doing wrong. If your baby is in fact teething, which seems to be very likely, then I can defintely recommend, freezing whole weat bagels. This is so good for the teething and it is healthy as well. Good luck!