The Talking Ape: How Language Evolved, Oxford University Press, 2002
The Slow Growth of Language in Children, in "The Transition to Language", Alison Wray, Oxford University Press, 2000.
Comprehension, production and conventionalization in the origins of language, in "The Evolutionary Emergence of Language: Social Function and the Origins of Linguistic", Chris Knight, James R. Hurford and Michael Studdert-Kennedy, Cambridge University Press, 1999.
Motivation, Conventionalization, and Arbitrariness in the Origin of Languagein "The Origins of Language: What Nonhuman Primates Can Tell Us", Barbara J. King, School of American Research Press, 1999.