Do you use a programming language that few HN readers have heard of?

If you do, tell us about the language and what you like about it.

As examples of what I mean by little-known and little-used languages, here are two programming languages that I think few HN readers know about or use (but correct me if my assumption is incorrect!)

Unicon - a successor to the Icon programming language with a particular strength in string processing:

http://btiffin.users.sourceforge.net/up/index.html

Euphoria - a small, cross-platform interpreted language:

https://openeuphoria.org/index.wc

What language are you using that is neither widely-used or widely-known? What do you like about it?