From iVillage:
By the end of month twelve a baby typically:
* May take one to two naps daily (yupp, anywhere between 10 minutes to 2 hours)
* Triples birth weight and is 29 to 32 inches long (tripled his birth weight at 6 months, but haven't checked the latest weight and length)
* Bangs two cubes together (or anything else for that matter)
* Puts objects into containers and then takes them out (loves doing this)
* Voluntarily lets objects go (knows how to give things to me when I say 'Sa'eed...give to ummi please')
* Shakes head "no" (hmm....not really)
* Has fun opening and closing cabinet doors (tak serik even if terkepit)
* Crawls well (yupp)
* "Cruises" furniture (check)
* Walks with adult help (uh-huh)
* Says "ma-ma" and "da-da" (and also tah tah, ba ba)
* "Dances" to music (only to hasbi rabbi)
* Interested in books and may identify some things (more interested to tear them apart)
* May understand some simple commands (hmm....knows to go to the bathroom when he's naked..ok tak?)
* Fearful of strangers (depends...)
* Shares toys but wants them back (likes to share, but sometimes grabs from people)
* May form attachment to an item (not really)
* Pushes away what he doesn't want (rather, he flails his arms)
* Prefers to push, pull and dump items (i don't even know what this means..haha)
* Pulls off hat and socks (doesn't mind the socks)
* Understands use of certain objects (everything is meant to be clanged together)
* Tests parental responses to behavior (sometimes, I guess)
* Extends arm or leg when getting dressed (hmm..almost always crawls away, but stays put after he's already dressed...go figure)
* Identifies self in mirror (he sometimes plays peek-a-boo)