Why should any developer learn more than one programming language?
This is an interesting question. Let’s think of it this way: Does a carpenter only use one type of saw? Does a mechanic only have one type of wrench? No. In short the answer is, as craftsmen of code, we are only as good as the tools that we know how to use; and programming languages are those tools. When it comes down to deciding on what language it is that you want to learn, the question you need to ask yourself is this. What type of developer do I want to be?
The range of possible languages is immense. There’s Object Oriented, Functional, Procedural, Multi Paradigm and the list goes on and on. Each layer of the technology stack requires a different toolbox of languages. While it’s very unlikely that anyone can ever be a master of all the languages needed, it should be possible to switch from one layer to the next fairly easily.