Hmmm. GP listed three languages which are not esoteric, and you've patted them on the back and shared three more which are not esoteric. Oops.

Esoteric language =/= any non-mainstream language.

Here's the definition from the esoteric programming language wiki, which is a lovely resource for anyone interested https://esolangs.org/wiki/Esoteric_programming_language:

> An esoteric programming language is a computer programming language designed to experiment with weird ideas, to be hard to program in, or as a joke, rather than for practical use.

Ummm...APL, Prolog, and Rebol are extremely esoteric. Their share of total code out there has got to be like less than 0.0001% and their paradigms are considered extremely weird and not for general consumption . I don't agree with the definition of esoteric included above and by the original poster.