The core language is heavily derived from PLI. The "system" is, well, a system. It includes a "development environment" (from the days before such a term existed), which I largely detest, a core procedural data language (the DATA step), a bunch of canned procedures (PROCs) (most of the useful ones are in extra, value-added, bleed-that-turnip, licensce for an additional fee, products), and a macro language.

There's little extensibility (there is, technically, through SAS/Toolkit, but it's a seldom-seen turnip bleeder), result being that there are some really annoying hacks done with Macro (many with my name on them). The main emphases are on data manipulation, reports, statistics, and graphics, with a heavy emphasis on hardcopy (rather than onscreen) reporting. This is changing with the growth of the web. Licensing is, in general, a major bitch. Per-seat will run $2-4K for a decent developer station, bulk licensing brings corporate costs down to ~$500 for a suitable number of seats. There's no runtime, so you've got to have a license per seat. Runs on anything, Mac to Mainframe, though current support is largely WinXX, Unix/Linux, and Mainframe. OS/2, Mac, VMS, and other platforms are largely unsupported moving forward.

The company is slowly moving into the 1980s. There's now online documentation available in several places (contrary to licensing policy), Google should turn it up, University of Chicago and UCLA IIRC.