The acquisition of the consonant system by a child acquiring Mexican-Spanish as her native language is described. During the earliest stages (from 1;7 to 2;1 years of age), the data showed several phenomena that could best be accounted for by assuming a central role for the word as the basic unit being acquired. The evidence for the centrality of words and word patterns in the child's early development is the main focus of the analysis. During the later stages (from 2;2 to 2;5), most of the evidence for words and word patterns disappeared, and the child's phonological system during this period can be described adequately in terms of phonemic contrasts and the more traditional phonological rules. The analysis covers the child's phonology at the beginning of the study (age 1;7), early phonological development (1;8 to 2;1), the learning of word patterns, the learning of phonemic contrasts, the child's development from 2;2 to 2;5, segmental system, co-occurrence of consonants, syllable structure, a model of phonology acquisition, universals of acquisition, and individual differences. (SW)