Most performance-critical code is written in lower level languages like C or C++, but Abra's question was where she should start. I've said this before and I'll say it again: I highly recommend Python as a first language. Thanks to this excellent tutorial, you can learn the syntax in a day or two. Python is very easy to learn and use, and it produces much clearer, more consistent, more concise, and more bug-free code than any other language (with the possible exception of Haskell) that I have ever used. Python also has a larger application domain than almost any other language. While you could just use it as a replacement for shell scripts, you can also use Python for desktop applications, games, server-side scripting, and web development. The only real downside of Python is that performance sometimes suffers due to the lack of a real compiler, but there are many remedies. The fact that Python is interpreted directly from the source files also means that the development time is drastically shorter than that of a language like Java, C, or C++. Eric Raymond's "Why Python" shows that even expert programmers use the language.