It's based on rewriting symbolic terms (similar to Lisp's s-expressions) using rules.
It then originally has a large library of facts and rules for a large amount of mathematical domains. This has been expanded over time into lots of knowledge about the world (physics, biology, astronomy, ...).
Programming is often done with multimedia-rich notebooks.
https://reference.wolfram.com/language/ref/entity/Planet.htm...
So it's some kind of knowledge-based system for mathematical related domains,
Is there a way to access the database without the language?