Looking through this collection, it looks like you can use at least the following programming languages to write programs in #
DOS :
#
C #
rexx #
prolog #
asm #
ada #
basic (several BASIC dialects, some compiled even) #
forth #
Cpp #
pascal #
modula2 #
lisp #
smalltalk #
fortran #
cobol #
logo #
perl #
python