Most of all, I think that it makes no sense to say that you are a “professional <<language_name here>> programmer.” You are a professional programmer, period. Perhaps, if you are “only two years in,” you have not yet been obliged to dive into many other language systems ... outside of University, that is ... but that day will swiftly come, and then it will come again and again, until you no longer think about it much. It simply becomes something that you do. It becomes something that you know with certainty that you can do, and, yes, it is a market advantage.
One thing that you’ll see is that pretty much all of these language-systems are far more similar than different. (And, on top of this, there are other systems that are truly different, such as Prolog.) As the gamut of languages that you have “seriously used” continues to expand, it does become easier.
And BTW ... this is one characteristic of this business that I have always enjoyed. Language-design, and the principles of “how to make a piece of silicon do what you want it to do” in general, have always been topics of particular interest to me, and the opportunity to learn “yet another one” is something that I look forward to. (I guess all those years of reading BYTE Magazine ... an APL interpreter in flowchart form ... Robert Tinney’s Pascal’s Triangle cover and all of that ... rubbed off on me somehow.) I don’t just do it because somebody else told me that I had to, nor necessarily paid me to do it. To me, the topic is both challenging and intellectually intriguing, and it’s cool if you can make a living at something that is also, in part, your hobby.