Lisp? Interesting but not required . . .assembly code, Lisp and Perl.
I can not remember if we are Perl independent yet? It is one of Barrys goals . . .
Assembly coding is gonna make a lot of sense.
http://www.shervinemami.info/armAssembly.html
Assembly language optimisation is more involved for ARM
I looked at some High Level Assemblers many years ago (I know it sounds contrary but these are amazingly easy compared to traditional assembler)