Software = Algorithms + User Interface + Bugs
Here is another one:
Programming Language = syntax + semantic + doc + libraries + IDE
The two first, syntax and semantic, are mandatory to define the language. The other ones are simply making it respectively understandable, useful, and usable.
The documentation contains the reference manual, the user manual, tutorials, and sometimes other kind of document that helps the transition from another language to this one. Ususally, a language is not coming up from scratch. It reuses known concepts (e.g. object oriented, multithreads) and can be very close to another existing language. For instance, Java syntax is similar to C, so dedicated books explaining Java for C programmers are very popular.
Libraries are making today the differences between languages. The object oriented paradigm spreads the concept of library driven by an API. And the web technology is a great producer of layers and libraries. As more and more libraries are integrated, the language becomes more and more useful.
IDE is now inevitable. Once a developer has tested a serious IDE like eclipse or visual C++, it's very difficult to go back to antic era where code is written in a text editor, compiled, debugged with an external debug tool (when it exists), and deployed through a shell script. The IDE provides the editor, compiler, and debugger, but also it suggests code patterns, completion, syntax highlighting, online documentation, and provides powerful navigation, packaging, etc.
