When variability matters more than meaning: the effect of lexical forms on use of phonemic contrasts.

During the first half of the 2nd year of life, infants struggle to use phonemic distinctions in label-object association tasks. Prior experiments have demonstrated that exposure to the phonemes in distinct lexical forms (e.g., /d/ and /t/ in daddy and tiger, respectively) facilitates infants' use of phonemic contrasts but also that they struggle to generalize the use of phonemic contrasts to novel syllabic contexts (Thiessen, 2007; Thiessen & Yee, 2010). Further, in prior research, infants have been provided only with experience in lexical forms that refer to novel objects, while many lexical forms in the natural environment do not have easily identified visual referents. The experiments in this article show that even lexical forms without referents can facilitate use of phonemic contrasts. Additionally, the results indicate that when lexical forms provide infants with enough variability (for example, a consonant followed by multiple different vowels), infants are able to generalize to novel contexts.