Yeah it had an almost sane reason initially - it was an investment bank, so it was designed to model the relationships between types of assets for simulations. But over the years they just got into the habit of using it for everything. It was somewhat like python, but with c-like syntax.
The 2nd language was a haskell-style functional language (but without all the things that make Haskell cool) that was meant to be used for modelling and building internal APIs on all the data that was shared across departments. It was absolutely horrendous.
I'm just starting to learn how language development works and like... of any language to try implementing, Haskell definitely seems like one of the most complex.
Like - one dev could reasonably implement a Forth or Lisp, but you need a long time window to finish a Haskell...
I did freelancing on a project with an custom language, which just compiled down to html/css/js - so nothing brand new. At first I thought it was neat. But as I peeled the onion back, I learned the origins of it was the CEO's brother who left the company. Then I started to see all the other cracks with it, like it was still compiling down to IE9.
After two weeks, I gave them a ultimatum that I either finish the project in a popular language, or I'm out.