This paper reports on a study of two girls about one year of age, part of a longitudinal study of the development of consonants by children learning their first language. Data are compared with a third child whose progress has been previously documented. Phone classes were grouped and phone trees analyzed for each child. A high level of variability was found to exist in word forms, as some words were initially correct, while others changed as sound mastery developed. Great selectivity was noted as the child decided which word to produce. Jakobson's claim of a universal order of sound acquisition is partly supported by developmental similarity among the children, yet each exhibits individual differences in phoneme acquisition strategy and lexicon. Four key assumptions are made from this study: (1) that a phonic core of remembered lexical items and their articulations is the permanent foundation of an individual's phonology; (2) that a child imposes increasing phonological organization on his stock of articulations and lexical representations; (3) that phonological development parallels phonological awareness; and (4) that an adult's ability to pronounce his language is a stage in his phonological development that exhibits the same kind of structure that is assumed in the phonological development of a child. (CK)