I list anything I've completed more than a tiny amount of paying work in. Maybe leaving something off if I think it'll hurt my chances, comp-negotiation, or get me shunted to shitty projects. Otherwise, if I got paid to do it, and shipped, it goes on the list.

However, I can barely "hello world" without mistakes or consulting references in any language I've gone more than a week without writing. So if I only listed languages & such that I'm ready to take a quiz over at any given moment, the list would always be very short. I'd miss a lot of job opportunities. Guessing that'd get me DQ'd from your process, but taking the alternative approach of only listing the very-small set of things I'm ready to work in right this second at any given time would surely have had very bad consequences for my career.