For a programmer how many programming languages need for learning?

Answer 1

For a programmer:
Using myself,
I am proficient in:
C++
C#
PHP
Python
C
Lua
Java
SQL
Javascript
Perl

Those are the languages I know
(I can use them efficiently and effectively to perform tasks at will.)
But most shockingly I prefer writing in the language of algorithms on paper, so I always carry a sharpened pencil, eraser, and a black pen on me. Hence I hardly do use these languages strictly (I then to write in these languages even combining them to express an algorithm) It's much easier to work with a combination of languages than a single one

As a programmer, that is, programming is your job, work. Chances will always necessitate a different programming language for a task. So odds are just continue in the learning the structure, framework, of the programming languages you know & when the circumstance needs a different language because of your understanding in the previous language the learning curve will be much lower than one who has no experience with programming languages. The first language I encountered was C++.
My heart still goes out to it. Since its the first. But I find myself preferring Lua and Perl, mostly because it gets the job done for me. In essence the programming language you learn doesn't matter, it's the principles behind them that if you know matters most. Didn't take me up to a week to learn Perl. Lua was more like a hobby to kill time.