I agree, there are way too many people in those languages that aren't disciplined about documenting what they're doing.

I think my argument certainly falls apart when considering those kinds of teams. Then again I have had the misfortune recently to experience some relatively undisciplined Java teams which creates a different set of problems. So on second thought maybe the discipline argument can go both ways.

What I typically have done when running a project was to require documentation of at least the inputs and outputs of the functions / methods they write. Also to make the names of those functions intuitive so people can get the gist of what it's doing just by reading the name. Also I definitely think it's a matter of discipline as well when people don't think clearly about what they're doing before they do it, which creates those wacky functions that return 5 different data types depending on the specific conditions.