I have to disagree, functional and object oriented languages produce very different solutions. Syntax is just the grammar. Compare e.g. Mandarin to a Latin based language and you will see what I mean. :)
But indeed, mastering more areas is even more impressive.
Few languages are pure FP or OOP, at least all the modern mainstream languages are hybrids. How different is python from c#? Ya, they are different but not incredibly so. Definitely not the diff between Latin and Chinese.
I am not saying you can't focus on a single language. But for example, if you know c# than you basically know java, and you basically also know php. You could easily pick up a pretty good understanding of these languages in under a week.
If you know c++ you could basically roll right into any of those languages I named above in under a week as well.
It is sort of difficult to do anything worth doing on the web unless you have experience with at a minimum Javascript, a serverside language(php, ruby, python, c#, whatever. You could maybe do nodeJS but if you are doing that you are probably already rolling deep in knowledge anyway) and have some experience with some kind of sql like database language. I'm not even counting html or css which aren't real languages but are still things you need to have some understanding of. Also there is a good chance you have a basic understanding of setting up apache and a linux server in a cloud environment.
If you're doing any of this stuff you have probably tinkered with mobile and maybe have some obj-c experience or at least java on android.
Everything is just so tied together these days unless you are just like, a day job programmer you probably have experience with a ton of languages and could get some code going in a bunch of others very very quickly.
I think you're conflating "knowing" a language with knowing the syntax of a language.
It was an easy transition into C++ syntax from my usual C#/Java programming, but the transition into thinking like a C++ programmer was not a simple or easy one. Weeks (months?) later, I am still learning how to be a "good" C++ programmer.
I remember "learning" PHP when I was younger and could probably program quite a few things with it still but I am definitely not a PHP programmer. I have no idea what is considered good or bad practice in PHP land. I could solve a bunch of Project Euler problems in PHP but I could not write a secure PHP application for actual use.
The same goes for most languages I can think of. I've fiddled around with it, written a few small programs, gotten a feel for the standard library, but unless I use that language on a decent sized project I have nothing but a superficial understanding of it.
If you already know how to program, "learning" a new language is trivial, you can do it in a few days, sometimes even a few hours. Learning to write "good" code in that language is not something that is easy to pick up or something that is transfers between languages, even closely related languages like C and C++ or C# and Java.
It's easy transiting from C++ to Java/C#, the the reverse transition is not as easy.
I would say that the "mental toolbox" of a C++ programmer includes a lot of things that also belong in a Java programmer's "toolbox" (i.e. classes, inheritance, virtual functions), which helps someone who knows C++ pick up Java relatively easily. But there are important aspects of C++ that are NOT in the Java toolbox, i.e. manual memory management, pointers, templates (which are way different from generics in java, by the way), these make the reverse transition harder.
We are in the dog days of summer, so the amount of good content to report here has probably gone down, leading us to puff pieces like this with very little content.
There is nothing wrong with it for what it claims to be. It is just content free and shouldn't be normally front page material, except right now there isn't much competition.
