J. Child Lang. (), –. Cambridge University Press DOI: .S Printed in the United Kingdom Precursors to onset clusters in acquisition* JUDITH A. GIERUT KATHLEEN M. O’CONNOR Indiana University (Received August . Revised March ) Two lawful relationships involving word-initial onset clusters have been advanced in the acquisition literature ; namely, that clusters imply affricates (Lleo & Prinz, , ), and that liquid clusters imply a liquid distinction (Archibald, ). This study evaluated and extended the validity of these implicational laws in a population of children (aged ; to ; ) with functional phonological delays who contributed extended speech samples for computational analyses. Results indicated that, for the most part, the composition of children’s sound systems were in compliance with the proposed laws ; however, there were noted asymmetries and apparent exceptions in the data. The asymmetries motivated an integration of the two laws to reveal a pattern of segmental–prosodic cyclicity consistent with deterministic models of phonological acquisition. The apparent exceptions highlighted the relevance of independent methodologies and offered a potential theor- etical alternative with the Resolvability Principle as directions for future research. Children’s acquisition of consonant clusters has received considerable at- tention from converging research perspectives. A primary emphasis has been the word-initial onset cluster, with three related issues guiding the general programme of study. One line of investigation focuses on children’s pro- duction of clusters and their corresponding errored outputs (Chin & Dinnsen, ; Smit, ). The goals are to document developmental stages in a child’s progression from production of - to -element consonantal sequences, and to capture the range of variation in cluster simplification relative to the adult target. Toward this end, acoustic and articulatory [*] This research was supported in part by a grant from the National Institutes of Health DC to Indiana University, Bloomington. We would like to thank Dan Dinnsen, John Archibald, and the anonymous reviewers for their input and helpful comments. Address for correspondence : Judith A. Gierut, Department of Speech and Hearing Sciences, Indiana University, South Jordan Avenue, Bloomington, IN -, USA. e-mail : gierutindiana.edu