Word learning by preschoolers with SLI: effect of phonotactic probability and object familiarity.

Purpose: In this study, the authors investigated whether previous findings of a low phonotactic probability/unfamiliar object word-learning advantage in preschoolers could be replicated, whether this advantage would be apparent at different "stages" of word learning, and whether findings would differ for preschoolers with specific language impairment (SLI) and typical development (TD). Method: Participants included 114 children: 40 with SLI, 39 with TD matched for age and gender, and 35 with TD matched for expressive vocabulary and gender. Comprehension and production were assessed during word learning and at post-test for words that varied in phonotactic probability and object familiarity. Results: Across groups, comprehension performance increased significantly from Day 1 to Day 2 and from Day 2 to Day 3, but there was no significant word/object type effect. Production performance increased significantly from Day 1 to Day 2, from Day 2 to Day 3, and from Day 3 to Day 4 for all groups, and there was a clear low phonotactic probability/unfamiliar object advantage during word learning but not at post-test. Conclusion: Results help to establish that preschoolers with TD and SLI show a low phonotactic probability/unfamiliar object production advantage during word learning that is not restricted to the first few exposures to words, but continues over time. This study illustrates how the interaction of phonological characteristics in nascent and extant words can affect word learning.