Children's first-language perception base takes shape gradually from birth onwards. Empirical research has confirmed that children may continue to fall short of age-based expectations in their speech perception. The purpose of this study was to assess the contribution of various perception processes in both reading and learning disabled children. A series of experiments was carried out with 450 Hungarian-speaking schoolchildren: learning disabled, reading disabled and typically developing control first-, second-, and third-graders. Data from seven perception tasks--focusing on acoustic, phonetic and phonological perception processes--were analysed. Results revealed that (i) there is no linear development in all groups across ages, (ii) correct performance is characteristic of both the perception process and the type of disability, and (iii) a specific pattern of organization can be drawn up as a factor in development. (Contains 1 table and 5 figures.) [This research was funded by a grant from OTKA, the Hungarian Scientific Research Fund.]