What are the key signs of slow development for a 12-month infant?

* Can't sit up from bed
* Can't stand without support
* Can't walk with support
* Haven't grown teeth.
* Really fussy at night.
* Resist solid food or choke on solid food.
* Can't say word like dada, gaga, kaka, baba, mama.
* Don't react to his/her name.
* Don't recognize his/her caregivers.
* Still need to take two naps a day.