From aardvark to ziggurat: A new tool for assessing children's use of rare vocabulary.

This study introduces a resource for examining children's use of low-frequency vocabulary and describes preliminary evidence of its validity. Using a corpus of >1400 transcripts from school-aged children, we derived a concordance of all words spoken by the children and generated a list of 2079 uncommon words we have called WERVE, the Wordlist for Expressive Rare Vocabulary Evaluation. Preliminary validity evidence for WERVE was examined through correlation analyses with WERVE results and other common language measures in a test sample of 112 children age 7 and 8 years. In addition, we replicated the correlation analyses using a sample of 38 eight-year-old children. WERVE results correlated strongly with established language sample measures and to a lesser but frequently significant degree with standardized test results. Results also showed developmental change from age 7 to age 8. Correlations ranged from medium to large. These results suggest that WERVE may be a useful tool for language sample researchers to explore.