You’ve landed a good job. You negotiated a high salary, plenty of vacation days, and flexible work hours.
Congratulations. But don’t stop thinking about your career just yet. Now that you know your way around your current programming language, it’s time to learn another one.
1) Languages go obsolete
Every programming language becomes obsolete at some point. COBOL isn’t used for new software anymore. Whatever language you’re using now will be obsolete, or at least on the downward trend, in 5-10 years. You don’t want to end up chained to one company (or worse, laid off from said company) with only an obsolete language on your resume.
Pick a language that looks to be on the upward curve, and learn it. Think of it as insurance against the future.
2) Languages express best practices
When someone creates a new programming language, they’re codifying a certain style of programming that they consider to be the best. After all, if Guido Van Rossum thought functional programming was the best style to work in, Python would have been a functional language.
One of the easiest ways to get deep into someone else’s ideas about the best way to program is to learn their language. Consider the learning experience a conversation you’re having with the language creator, trying to learn how they think programming should be done.
You’ll probably agree with them on some things, and disagree on others. Take the things you like - the parts of the language that make some best practices easier - and find ways to incorporate them in the language you’re currently using.
3) Languages don’t do everything well
Most of the general-purpose programming languages we’ve got are actually really good at just one or two things, and terrible at others. PHP is a great scripting language, but pushing it to express a complicated DSL leads to code that’s hard to read and painful to write.
Picking up a new language gives you a larger toolbox to draw on, so when it comes time to build that internal website, or reporting system, or distributed image processing software, you’ll be able to use the best language for the job.
4) Languages lead to jobs
This one almost goes without saying. You can’t land a Ruby job without learning some Ruby. You need to know C++ (or Objective-C) to work in the games industry. If you want to switch from web development to scientific computing, learning a new language is your best bet.
5) Languages teach programming fundamentals
Do you know what a monad is? How about S-expressions? Learning a language that’s radically different from what you normally work in (say, Haskell for Python devs) can teach you new programming concepts. You’ll learn new ways of thinking about programming, and new ways to approach traditional programming problems.
In the end, learning a new language (or several languages) is all part of becoming a mature, experienced developer. If you want to prepare for the future, expand your programming horizons, and keep a secret weapon (or two) in your dev toolbox, then you should learn a new language.