Answer:
Though I am only two words I have thousands of letters in me
What always ends everything?
My first half means container. Not a lot of people understand my language. What am I?
I go up and down at the same time. Up towards to sky and down towards the ground
Curtail me thrice I am a youth; behead me once a snake; complete I'm often used in truth when certain steps you'd take.
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.