I agree on the talking that many 12 month olds just look at you when you talk and don't respond. Two words will be a lot longer coming. As for the stairs a child that can crawl can climb stairs - hence the need for safety gates from a very young age. As for going down - mine turn around backwards and go down a stair at a time. I do not like the sit on the bum and go down forwards because if a foot catches or they lean too far forward they fall. Going backwards down there are a lot less issues. Between 15 -18 months I start them going down or after they are walking properly. Mostly I give them all a chance to do it and if they can fine, if they are too scared or unsure I pick them up and carry them. Mine know to sit at the top of the stairs till I give them the go ahead to come down or go up. The really little ones that don't are secured till others are down. I don't let them stand and use the railing till they are closer to 3 mostly because of size as in not reaching up to get it. Not holding a bottle at a year shouldn't be an issue because a child should be on a cup during the day by a year and would be if it was introduced by 9 months like it should be. A child will act as helpless as you let them.