As an alternative to aligning language with the cognitive and parole with
the social, we could follow Hjelmslev or Halliday and treat parole as the
instantiation of langue - parole as the weather and langue as the
climate to use an analogy Halliday has suggested. Then langue, the
system, and parole, its instantiation in text (or process if we want a
dynamic view) can both be read as social (or social/psychological if you
will). I think this kind of re-reading of Saussure would interface
linguistics with activity theory much better than a cognitive vs social
split.
Jim Martin