Language development in persons with cri du chat syndrome (CDCS) has only been described in very general terms. Three tendencies have been noted in the literature: First of all, there is a discrepancy between chronological age and linguistic age in children with CDCS. Second, there is a discrepancy between receptive and expressive linguistic abilities in these children. Third, their articulation is characterized by omissions and substitutions. However, little is known about the exact nature of these articulation problems. In this paper longitudinal phonological data from a Norwegian girl with CDCS are presented and compared to data from normally developing Norwegian-speaking children.