Progress in an extensive, linguistically oriented program of research on child language development is reported. The ultimate purpose of the research is to contribute to a general theory of human language behavior; more immediate goals are the increased understanding of language development processes and improved characterizations of particular languages. The first stage of research, the project "Aspects of the Acquisition of English Phonology," has four principal areas of study: (1) production of initial English consonants; (2) recognition of initial English consonants; (3) phonotactics, in particular the production and recognition of certain English consonant clusters. The state of each of the principal areas and plans in each area during the remainder of the grant period are presented. Substantive results reported concern (1) modal order of acquisition, (2) Shvachkin research method, and (3) value of multiple approach. By-products of the research include the following: (1) new interdisciplinary focus to child language research at Stanford; (2) new means of information exchange on child language research; (3) new publication of working papers; and (4) child language data archive. Future research will concentrate on other parts of English phonology using the same multiple approach and the extension of the study to the phonology of other languages. (DB)