The big languages are popular for a reason: They offer a huge foundation of open source code, libraries, and frameworks that make finishing the job easier. Sometimes the vast resources of the popular, mainstream programming languages aren’t enough to solve your particular problem. Sometimes you have to look beyond the obvious to find the right language, where the right structure makes the difference while offering that extra feature to help your code run significantly faster without endless tweaking and optimizing. This language produces vastly more stable and accurate code because it prevents you from programming sloppy or wrong code.
The world is filled with thousands of clever languages that aren’t C#, Java, or JavaScript. Some are treasured by only a few, but many have flourishing communities connected by a common love for the language’s facility in solving certain problems. There may not be tens of millions of programmers, who know the syntax, but sometimes there is value in doing things a little different, as experimenting with any new language can pay significant dividends on future projects.
The following six languages should be on every programmer’s radar. They may not be the best for every job — many are aimed at specialized tasks. But they all offer upsides that are worth investigating and investing in. There may be a day when one of these languages proves to be exactly what your project — or boss — needs.
Erlang: Functional programming for real-time systems
Erlang’s secret is the functional paradigm. Most of the code is forced to operate in its own little world where it can’t corrupt the rest of the system through side effects. The functions do all their work internally, running in little “processes” that act like sandboxes and only talk to each other through mail messages. You can’t merely grab a pointer and make a quick change to the state anywhere in the stack. You have to stay inside the call hierarchy. It may require a bit more thought, but mistakes are less likely to propagate.
The model also makes it simpler for runtime code to determine what can run at the same time. With concurrency so easy to detect, the runtime scheduler can take advantage of the very low overhead in setting up and ripping down a process. Erlang fans like to flourish about running 20 million “processes” at the same time on a Web server.
If you’re building a real-time system with no room for dropped data, such as a billing system for a mobile phone switch, then check out Erlang.
Go: Simple and dynamic
Google wasn’t the first organization to survey the collection of languages, only to find them cluttered, complex, and often slow. In 2009, the company released its solution: a statically typed language that looks like C but includes background intelligence to save programmers from having to specify types and juggle malloc calls. With Go, programmers can have the terseness and structure of compiled C, along with the ease of using a dynamic script language.
While Sun and Apple followed a similar path in creating Java and Swift, respectively, Google made one significantly different decision with Go: The language’s creators wanted to keep Go “simple enough to hold in one programmer’s head.Thus, there are few zippy extras like generics, type inheritance, or assertions, only clean, simple blocks of if-then-else code manipulating strings, arrays, and hash tables.
The language is reportedly well-established inside of Google’s vast empire and is gaining acceptance in other places where dynamic-language lovers of Python and Ruby can be coaxed into accepting some of the rigor that comes from a compiled language.
If you’re a startup trying to catch Google’s eye and need to build some server-side business logic, Go is a great place to start.
Groovy: Scripting goodness for Java
The Java world is surprisingly flexible. Say what you will about its belts-and-suspenders approach, like specifying the type for every variable, ending every line with a semicolon, and writing access methods for classes that simply return the value. But it looked at the dynamic languages gaining traction and built its own version that’s tightly integrated with Java.
Groovy offers programmers the ability to toss aside all the humdrum conventions of brackets and semicolons, to write simpler programs that can leverage all that existing Java code. Everything runs on the JVM. Not only that, everything links tightly to Java JARs, so you can enjoy your existing code. The Groovy code runs like a dynamically typed scripting language with full access to the data in statically typed Java objects. Groovy programmers think they have the best of both worlds. There’s all of the immense power of the Java code base with all of the fun of using closures, operator overloading, and polymorphic iteration.
Finally, all of the Java programmers who’ve envied the simplicity of dynamic languages can join the party without leaving the realm of Java.
CoffeeScript: JavaScript made clean and simple
Technically, CoffeeScript isn’t a language. It’s a preprocessor that converts what you write into JavaScript. But it looks different because it’s missing plenty of the punctuation. You might think it is Ruby or Python, though the guts behave like JavaScript.
CoffeeScript began when semicolon haters were forced to program in JavaScript because that was what Web browsers spoke. Changing the way the Web works would have been an overwhelming task, so they wrote their own preprocessor instead. The result? Programmers can write cleaner code and let CoffeeScript turn it back into the punctuation-heavy JavaScript Web browsers demand.
Missing semicolons are only the beginning. With CoffeeScript, you can define a function without typing function or wrapping it in curly brackets. In fact, curly brackets are pretty much nonexistent in CoffeeScript. The code is so much more concise that it looks like a modernist building compared to a Gothic cathedral. This is why many of the newest JavaScript frameworks are often written in CoffeeScript and compiled.
Haskell: Functional programming, pure and simple
For more than 20 years, the academics working on functional programming have been actively developing Haskell, a language designed to encapsulate their ideas about the evils of side effects. It is one of the purer expressions of the functional programming ideal, with a careful mechanism for handling I/O channels and other unavoidable side effects. The rest of the code, though, should be perfectly functional.
The community is very active, with more than a dozen variants of Haskell waiting for you to explore. Some are stand-alone, and others are integrated with more mainstream efforts like Java (Jaskell, Frege) or Python (Scotch). Most of the names seem to be references to Scotland, a hotbed of Haskell research, or philosopher/logicians who form the intellectual provenance for many of the ideas expressed in Haskell. If you believe that your data structures will be complex and full of many types, Haskell will help you keep them straight.
Julia: Bringing speed to Python land
The world of scientific programming is filled with Python lovers who enjoy the simple syntax and the freedom to avoid thinking of gnarly details like pointers and bytes. For all its strengths, however, Python is often maddeningly slow, which can be a problem if you’re crunching large data sets as is common in the world of scientific computing. To speed up matters, many scientists turn to writing the most important routines at the core in C, which is much faster. But that saddles them with software written in two languages and is thus much harder to revise, fix, or extend.
Julia is a solution to this complexity. Its creators took the clean syntax adored by Python programmers and tweaked it so that the code can be compiled in the background. That way, you can set up a notebook or an interactive session like with Python, but any code you create will be compiled immediately.
The guts of Julia are fascinating. They provide a powerful type inference engine that can help ensure faster code. If you enjoy metaprogramming, the language is flexible enough to be extended. The most valuable additions, however, may be Julia’s simple mechanisms for distributing parallel algorithms across a cluster. A number of serious libraries already tackle many of the most common numerical algorithms for data analysis.
The best news, though, may be the high speeds. Many basic benchmarks run 30 times faster than Python and often run a bit faster than C code. If you have too much data but enjoy Python’s syntax, Julia is the next language to learn.

Polina Mikhan
Business Development Manager
You completely forgot Fortran and LISP… people forget the coolness of sparse minimalism so quickly.