Picking a programming language is very important, because for me I have learned a lot of languages that didn't help me much, Like I learn Perl because I naively thought it was a very cool hot thing at that time, but it turned out very few people were using Perl except like systems managing industry and I was stuck in this world of pro for like a year, and I had also learned PHP and I was doing a lot of PHP programming, PHP from long time ago has being considering a sort this abomination language that a lot of developers don't really respect much, now personally I think is a fantastic language, you can so much with it, and yet kind of unstructured and if you don't use correctly it can lead to very messy code design, but it doesn't mater what you really think, the fact is many developers these days look down on PHP developers.
I also had learned ActionScript for flash programing flash was very hot for a while and then flash flied out, in this article I'm gonna a talk about to 3 languages to learn in 2020.
We can see that Java is used pretty heavily. Based on this table of Back-end (Server-side) in most popular websites from wikipedia.org
So let's start with PHP, I think it's a really great language if you really want to get your own project up and running, but the problem is yet the reputation isn't very good and for beginners I don't really recommend that you get off one this because it's going to start you off on the wrong foot and just kind of cripple you through the whole interview processes, although I think if you were applying to PHP heavy companies, and there is a few of them especially startups then it's pretty good actually and it's very easy language to learn.
Great language too, and the great thing about java is it can also be used for Android development so it can get you into that, if you check the table above you may notice that it has been growing very quickly recently, and I believe that there a lot of Jobs for Android developers nowadays, and I think that Java is really good programming language to get into as soon as you master the basics you may get into Android Development as well, and probably there is some less competition there for speciality of android development, mainly reservation about Java would be it this the language used by many college courses so every single computer science student may already know Java there is a ton of competition for Java itself and Java is free. The other thing about Java is it maybe more robust more than other languages, and it's just not really fun to write at least for me, like you have to compile the code every time you make change and it's just slow to do that, and when you want to run is on web development server it takes a lot of resources.
Golang is the newest language invented by Google, it's really considered like a niche language.
C++ if probably one of the most difficult languages to code with because you have to do a lot of your own memory management, and it's lower level language in general, but the great about it is that it's highly performante, and it used in all over the places you may see it in mobile development, you may see it on the backend where people want to do some complicated algorithm tasks, but generally I think if you are a beginner you shouldn't start with C++ unless you know what you are doing because it's just a more complicated language to get into, and tasks it is used for are usually more advanced. And for those wondering C++ is pretty much like C but C++ just adds on Object Oriented Programming, so that it is much more object oriented.
C# is basically Microsoft version of Java and if you plane to apply to Microsoft then C# is a good one use.
There is other language you should have to look at like Python, I think Python is a great one, you can see in the table above that it's used in many different companies, several years ago a lot of companies were using PHP to power their web backends for now many have switched over to use python, python is a simple language to go with it's interpreted which means you don't have to compile it every time you make a change, and so that fast iteration cycle makes it very quick to learn, it has more features like OOP (Object Oriented Programming) and also you don't have to manage the memory by yourself which I think it's going to be key thing to look for when you stating out.
RubyOnRails is not really being used by a lot of large companies anymore although there are some startups that are using it.
I also wanted to talk about mobile development since that's a pretty hot area so I mention that there is Android Development which is done in Java, there is also these newer language Kotlin but there is something very cool which released recently for developing mobile applications for cross platforms IOS and Android using single codebase, I'm talking about flutter framework which is now one of the best framework in the world of mobile development, so I recommend you to have a look at that.
So to wrap thing up I think Python is pretty good general language and it's good for a lot of backend development, if you want to get into IOS development go with Swift and for Android development just pick Java or Kotlin both are great languages, although I recommend you to pick flutter, those are basically the languages that I would go with in 2020, and then on side pickup some JavaScrip and of course HTML, CSS just for fun so you can do some web development because that's probably good skills to have in general.
So I hope that was useful if you have any questions just contact me at /contact page. thanks and Good luck.