The construction of a first phonology.

Although it is generally accepted that phonological development is grounded in phonetic learning, there is less agreement for the proposition supported here, that the first phonological structuring constitutes a developmental discontinuity. Data from the phonetic and lexical learning of Finnish consonant duration are presented to illustrate the role of (1) child selection of adult words for early context-supported production based on phonetic learning and (2) child adaptation of adult words to an idiosyncratic template for later production as part of an incipient system. We argue that the latter, but not the former, reflects the construction of a first phonology.