A sample of 178 children have been followed annually for the past five years, to assess the development of speech perception abilities in early deafened children using a multichannel cochlear implant. A subset of these children who acquired deafness prior to the acquisition of language (prelinguistic) have shown continued improvement on a hierarchy of pediatric speech perception tests throughout the follow-up period. Implantation at an early age appears to improve the prognosis for development of more difficult speech perception skills. In addition, there appears to be a positive relationship between the emphasis on oral listening skills and the rate of acquisition of speech perception abilities. Throughout the duration of the longitudinal study, several new speech processing strategies have been introduced for the Nucleus implant system. The most recent (SPEAK) is an adaptive strategy that varies the rate of stimulation and the number of electrode is stimulated according to the frequency characteristics of the speech signal. SPEAK attempts to represent the dynamic nature of speech and provides improved spectral detail by virtue of 22 closely spaced electrodes. A sample of 34 prelinguistically deafened children demonstrated significant improvements in speech perception within six months of conversion to the new processing strategy.