@incollection{Halliday79-proto,
  author	= {Halliday, M. A. K.},
  editor	= {Bullowa, Margaret},
  year		= {1979},
  title		= {One child's protolanguage},
  booktitle	= {Before speech: the beginnings of interpersonal communication},
  publisher	= {Cambridge University Press},
  address	= {Cambridge},
  pages		= {171--190}
}