Carmel O'Shannessy gave a talk titled "Evidence against intentionality
in the emergence of Light Warlpiri, a mixed language in northern Australia" at the workshop: Intentional Language Change, at the University of Leiden, The Netherlands, Sept 27-28.

Abstract:

Some researchers see a strong role for deliberate decision in the emergence of mixed languages. But in the case of Light Warlpiri, a mixed language spoken in north Australia which combines Warlpiri, Aboriginal English and/or Kriol, the evidence points away from deliberateness. Light Warlpiri appears to have been formed through a two-step process. First, adults directed code-switched speech to children consistently in a baby talk register, combining languages in a pattern which is like that of Light Warlpiri. Second, children processed the code-switched speech as a single system, conventionalized it and added innovations in the verbal auxiliary system. There is no role for deliberateness at the innovation stage of the development Light Warlpiri – the child speakers re-analyzed and grammaticalized existing structures and developed new structures. Now that Light Warlpiri is stabilizing, deliberateness does play a role in its continuation as it signals the identity of its speakers as young Warlpiri in one community.