IMHO, if you want to be a better programmer, you should eliminate language dependency.
No one can `master` one language, but good programmer can use new language easily with less effort.
You know, people say that, but I don't quite buy it. You need to invest a lot of time in a language before you fully understand its ecosystem, quirks, strengths, and weaknesses. I believe that the time is better spent learning new algorithms. It's better to be able to implement hard algorithms in one language, than to be able to implement easy algorithms in a hundred.