>>1034204
well
1. C, literally all the suckless software is written in C, no? And if you do anything GUI toolkits aside with Unix you'll be working with APIs that are written for/with C, so using C yourself means one less step to using the API. You've also got gdb, ltrace, valgrind, and other friends.
Speaking of, these are the languages supported by gdb: C, C++, D, Go with gccgo or 6g, Objective C, OpenCL C, Fortran, Pascal, Rust, Modula-2, Ada. If your language isn't in this list, it sucks :^)
2. Perl, for some values of unix philosophy
3. Awk, if Perl is too useful for you
4. Forth, for simplicity and minimalism more than unix
If you emphasize the code quality and code not getting too complex parts of suckless, you can argue for languages like Ada, D, Go, maybe Scheme. Whether that argument will be accepted, I dunno. Write some good code and present it along with your argument; bonus points if it's a quality rewrite of some shit C.