I have been developing for a very long time, I started writing code in Visual Basic 5 before .Net was a thing. I knew one language basically VB, I had learned Basic about 10 years before in High School and thought how great it was to start writing programs for Windows. It was awesome, I could make utilities to do a lot of different things. I had no idea that I was in a very small club of developers, those that were using VB, everyone else was writing C++ or Visual C++ and they were able to write some awesome stuff, compared to my little cheesy stuff, you could only write games and the like in one of those C variants, which I only knew existed.
Fast forward 10 years or so, I was starting to write VB.Net apps and ASP.Net stuff, and thought I was a great developer and that I was marketable. Started looking for a new job and found there was little to no call for VB still everyone wanted a variant of C although it had become C# so I realized I needed to do something that I had put off for a very long time, learning new languages. I started by trying to expand my web languages into PHP and javascript, I realized I had all but shot myself in the foot by learning VB/Basic, I was having a very hard time getting the language mechanics of both of them, but kept on trying to learn them. PHP was awesome and powerful like a C language seemed it could be and Javascript allowed me to start doing some of the more funky things in ASP.Net that the company I work for had not yet started to do. Then I started to hear about jQuery, I noticed it had a much simpler way of doing things and you really did not need to know as many of the little nuances of each browser engine and you could really start to do some really amazing things, like manipulating the DOM and doing some AJAX stuff which is amazing and really took my ASP.Net stuff to a new level. During this learning I guess the languages I was writing started to make it easier for me to learn new languages. The company I work for decided to use Dundas for dashboards, which made it possible to really customize the dashboards, the only real hurdle was it used C# and I had yet to learn it, but it seemed kind of easy to pick up, I am guessing it was the PHP, javascript, and jQuery programming that made it easy to start to pick it up. Now I have been writing C# code within Dundas for over a year and have actually created a couple of apps using C# in Visual Studio and now it feels so much easier to learn the new languages, not like it was 10 years ago when looking at C code made me think it was a foreign language.
Using these languages when I could have just as easily stayed a VB/ASP.Net developer has allowed me to become a much more valuable member on the development team and to become very important to the team, which is never a bad thing. I believe it also will have made me more marketable although I am still a little scared to try to get a C# job and I am also a little scared to try a PHP job as well. The only other thing I wish I would have learned as a young developer is graphic design, not to become a designer but just so I could make my apps or webpages look better and more marketable. I highly recommend young developers to learn as much as they can and to maybe start with a C language, which will make it easier to pick up other languages. Those devs should probably also try to learn some design stuff as well, that is almost a requirement now. Broaden your language horizons so that you may be much more marketable and this will definitely help you in the long run.
Later for now.