Twelve pairs of three-year-olds and twelve pairs of five-year-olds were monitored in a play situation; their transcribed speech was examined for use of nominal reference, with attention to pronominalization and ellipsis. For the corpus of nominal references, there was a clear trend toward normal progression from specific indefinite to definite to reduced form, and from specific definite to reduced form. When reduction did occur, pronominalization was the preferred form for maintaining reference, followed by demonstrative reference and ellipsis, in that order. Substitution and comparative reference were rare. The magnitude of scope, measured in number of clauses during which reference was maintained, did not positively affect the restoration of the full form. The effect of a cued condition was to permit reduction of initial referent form. The effect of other conditions (pretend, new referent, new information, no response, identification) was to block reduction. Within each situational condition, the incidence of utterances was different for the two age groups. However, the proportion of utterances that were reduced by the older children was not significantly different from the proportion reduced by the younger children in any of the conditions. (JB)