This article reviews research on speech and language abilities in people with cri du chat syndrome (CCS). CCS is a rare genetic disorder, with an estimated incidence between 1 in 15,000 and 1 in 50,000 births, resulting from a deletion on the short arm of chromosome 5. In general, individuals have delayed speech and language development, and some never develop spoken language. Their receptive language is better than their expressive language, although both are delayed. Regarding phonetics and phonology, substitutions, omissions, and distortions are frequent; consonant inventories are small; syllable shapes are restricted; and vowels are variable and overlap with each other acoustically. Persons with CCS have been found to inflect words from all major word classes. Little is known about syntactic skills, but some individuals are reported to express themselves in utterances of two or more words. Knowledge about speech and language development in CCS is sparse, and the need for more research is considerable. (Contains 8 tables.)