my 2 year old daughter sometimes rocks back and forth on the couch, rocks from side to side when standing and kind of hums or sings songs, will hold on to things like tables and bounces up and down and sometimes jumps up and down...it happens many times everyday. i was thinking that it had to do with self-soothing - she does it when she's tired, nervous, excited. she seems fine in every other way except her expressive speech is a little delayed but so was my son's - her receptive is great, she understands everything we say, follows directions... she makes eye contact, plays appropriately with toys, etc. but i'm starting to get nervous that maybe those behaviours could indicate autism or something else.