> Almost all of Linux userspace is written in C. Depends on what you count. Qt can be seen as (part of the) Linux userspace. KDE applications are usually writt

> Almost all of Linux userspace is written in C. Depends on what you count. Qt can be seen as (part of the) Linux userspace. KDE applications are usually written in C++ (partially in QML+JavaScript), Gtk applications are written in C or Vala (a few in C#). If you don't count DE frameworks basically the only thing left would be libc, which of course is C (but available in some form under every noteworthy OS).