Well, it is certainly concise to represent formulae and equations in Mathematica, but that isn't what makes it a concise language. That I think is owed to Math

Well, it is certainly concise to represent formulae and equations in Mathematica, but that isn't what makes it a concise language. That I think is owed to Mathematica being an heir of LISP that implemented m-expressions so cleanly that M doesn't even feel like a homoiconic language. Most other LISP-derivates (like Clojure) stuck to s-expressions, which are historical baggage more than anything else. Some day I'm sure we'll get an m-expression version of Clojure. Of course in practice one defines new DSLs quite often in Mathematica. And it comes with a variety of DSLs "built-in", mainly for user interface construction, vector graphics, mathematics, and statistical computations. Disclosure: I too work for WRI.