Previous studies have shown that by 11 but not by 10 months infants recognize words that have become familiar from everyday life independently of the experimental setting. This study explored the ability of 10-, 11-, and 12-month-old infants to recognize familiar words in sentential context, without experimental training. The headturn preference procedure was used to contrast passages containing words likely to be familiar to the infants with passages containing words unlikely to have been previously heard. Two stimulus words were inserted near the beginning and end of each of a set of simple sentence frames. The ability to recognize the familiar words within sentences emerged only at 12 months of age. The contrast between segmentation abilities as they emerge as a result of everyday exposure to language, as assessed here, and those abilities as measured in studies in which words are experimentally trained is discussed in terms of memory-based mechanisms.

This study was undertaken as a sequel to DePaolis (1991) to explore the role of sonority in constraining the word identification errors of normal listeners. The data from 9 subjects from DePaolis's study were used to examine the phonological relationships, defined by the Sonority Sequencing Principle (Jespersen, 1904), between response errors and stimulus targets - a methodology previously employed in the analysis of target-related neologisms (Christman, 1992b, 1994). The present study found that, although sonority may constrain onset-driven word-search processes, sonority and lexical phonostatistics may constrain coda-driven word-search processes. These findings are consistent with those obtained from the productive errors of aphasic subjects (Christman, 1994). Taken together, the results of these studies support a role for sonority in phonologically based aspects of word identification and word production.