Volume 1: The Data. Contents: D.I. Slobin, Introduction: Why Study Acquisition Crosslinguistically? Part I:Spoken Languages. J.G. de Villiers, P.A. de Villiers, The Acquisition of English. A.E. Mills, The Acquisition of German. E.V. Clark, The Acquisition of Romance, with Special Reference to French. E. Ochs, Variation and Error: A Sociolinguistic Approach to Language Acquisition in Samoa. A.A. Aksu-Koc, D.I. Slobin, The Acquistion of Turkish. Part II:Signed Languages. E.L. Newport, R.P. Meier, The Acquisition of American Sign Language. Volume 2: Theoretical Issues. Contents: J.R. Johnston, Cognitive Prerequisites: The Evidence from Children Learning English. T. Givon, Function, Structure, and Language Acquisition. A.M. Peters, Language Segmentation: Operating Principles for the Perception and Analysis of Language. B. MacWhinney, Hungarian Language Acquisition as an Exemplification of a General Model of Grammatical Development. D.I. Slobin, Crosslinguistic Evidence for the Language-Making Capacity. M. Bowerman, What Shapes Children's Grammars?