While we learn all these languages , how can we remember such a huge amount of information in each programming language ?

Answer 1

The devil isn't so black as he is painted ;)
Just code.

Answer 2

coding dude, you should be learning with a porpouse, only trying to memorize this stuff it's useless, vane, and naive

Answer 3

All of them share some concepts like variables, functions and loops, so learning them in any programming language will help you understand almost every other one.
Yes, there are language specific concepts, and this is where your psyche comes into play, you have to decide which programming language is going to be your mother language, and try to master it.