/sys$common/syshlp/helplib.hlb DCE_IDL, DCL Command Interface, QUALIFIERS, /LANGUAGE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

      /LANGUAGE [={CC | CXX | FORTRAN}]
      /LANGUAGE=CC (default)

        This qualifier is equivalent to the -lang argument in the
        universal syntax.