Sorry. I was discussing languages people actually use.
Ah, so because I use it I'm not a person. Gotcha. [/sarc]
Usage of a language is irrelevant to the discussion of language features, or it's 'style'. There are many unpopular languages which I would like to learn some level of proficiency [more than just "I've heard of..."], precisely because, if nothing else, they will give me more tools & understanding to address the problems of problems [which programming is]
LISP [functional programming],
Prolog [Logic/goal-based programming],
Forth [advancement/development via continual addition of 'words'; stack-based],
PostScript [addressing imaging issues; stack based],
Snobol [string manipulation; from reports an order-of-magnitude more 'powerful' than regex];
these have [vanishingly?] small user-bases [in general programming] but are interesting in 1. what they allow, 2. how they address programming in-general, 3. how they address their own 'focus'/specialty.
To dismiss (out of hand) a language because it is unpopular from qualifying for consideration in a discussion about some general-attribute indicates nothing about the language brought up, but it does say something about you, and not really a good thing: that you are a "me too" sort of programmer, going with the flow and, more importantly, not thinking about your trade -- and if you are not thinking about your trade, then how can you be trying to improve it, either by improving yourself or by improving a language, or even improving methodology ("best practices")?