Is kdeveloper ONLY C++? From what it looks like thats a yes.
but it isn't :-P
following the featurelist you'll notice:
15 supported languages including Ada, C, C++, Objective-C (via C support), SQL, Fortran, Haskell, Java, PHP, Pascal, Perl, Python, Ruby, Bash, XUL
so in most cases you'll find that your language of choice for development is supported, hmm, that is unless you are looking for an AROS ide or something :-D