Both Scheme and Common Lisp have been open standards since their inception. And both have excellent IDEs available, both commercial and open-source (Clozure CL for Common Lisp and Racket for Scheme).

I did my masters thesis in 1986 on Coral Common Lisp on a Macintosh Plus with 800k floppies and 1 MB of RAM. It had an IDE that would still be competitive today, indeed is in some ways still superior to anything available today. All this was possible because it was Common Lisp and not C. The language design really is a huge factor.

(Coral has today evolved into Clozure Common Lisp, which is completely free and open (Apache license). You really should try it.)