This study proposes that children's phonological behavior at Stage VI of sensorimotor development may show markedly decreased variability compared to children at Stage V. According to Piaget, sensorimotor development during Stage VI is distinguished from preceding stages by the onset of representational ability and ability to form mental combinations. Twenty normally developing children, half of whom were at the "one-word" stage and the other at the "two-word" stage (respectively V and VI), were seen for a minimum of two and a maximum of four sessions within a period of six weeks. A controlled experimental playroom with normal environmental stimuli and a standard set of objects and books were used. The Ordinal Scales of Psychological Development (Uzgiris and Hunt, 1975) were administered, and samples of nonimitative speech were taken. The data were subjected to analyses of production variability, optional processes, and phone classes. Results indicated: (1) Children at Stage VI manifested significantly less production variability than at Stage V; (2) a greater relative number of optional processes were necessary in describing Stage VI phonological behavior; (3) Stage VI children showed a greater number of phone classes per child; and (4) a marked decrease in variability correspondence of word-initial sounds was evident. The study concludes that there is significantly less variability in the phonological behavior of children at Stage VI than at Stage V, suggesting a degree of discontinuity in phonological development. (MHP)