(Compulsive editors ourselves, we welcome anyone being driven crazy by a frozen typo or solecism in their comment to obtain relief by emailing hn@ycombinator.com.)
A bit like how Crockford jams DEC64 into everything, but Wolfram's been doing it for years
In particular, I suggest reading about the evaluation procedure: http://reference.wolfram.com/language/tutorial/EvaluationOfE...
In short, it's a term-rewriting language with a particularly complex (although carefully crafted) rewrite strategy. Rewriting and evaluation strategies have a rich base of history and literature to read up on too.
But really, the best way to get the flavor of Mathematica is to play with it. I recommend downloading a free trial, since the desktop application is much more responsive and interactive than the online version.
It's pretty fun and, once you get the hang of it, surprisingly useful. And I mean that both ways: 1) It's surprising how useful it is and 2) It's often surprising when it's useful. It was a pleasant surprise when I discovered how useful it can be and it's always pleasant when I'm surprised by an opportunity to use it.
But it requires more time than 1 hour to study. Maybe I fill find time some day to read it.
If would be nice if during presentation the explained at least one feature which is absent in other languages and makes it possible to build models more compact yet more widely applicable than other languages allow. Just one language feature, but understandable for programmers.
Because the hocus-pocuses with selecting something from internet and printing on screen doesn't help to understand.
Or even better: demostrate some impressive real world application (other than Mathematica itself)
There are, however, lots of interesting things that most other languages don't have. For example, extremely powerful pattern matching: https://reference.wolfram.com/language/guide/Patterns.html
And a form of predicate dispatch: https://reference.wolfram.com/language/tutorial/TheOrderingO...
Or a universal data representation: http://reference.wolfram.com/language/ref/FullForm.html
Or the ability to extend the syntax by adding to a 2D operator precedence parser's dispatch tables: http://reference.wolfram.com/language/Notation/tutorial/Nota...
This is all to say nothing of the standard library, but beyond evaluation strategy, what parts are "library" and what parts are "language" is so blurry as to be practically meaningless.
Do you know interesting programs/systems developed with WL?
Was going to type up something here for onlookers, but on mobile at the moment.