Answer:
My first half means container. Not a lot of people understand my language.
Born in the ocean and white as snow. When I fall back to water I disappear without a trace.
I wiggle and cannot see; sometimes underground and sometimes on a tree. I really don't want to be on a hook and I become a person when combined with “book”.
I have a neck and no head two arms but no hands. I go with you to school I go with you to work.
I am born in fear raised in truth and I come to my own in deed. When comes a time that I'm called forth I come to serve the cause of need.
No matter how little or how much you use me, you change me every month.