estimating vocabulary size

[Margaret Fleck]

Can anyone point me at research estimating the difference between a toddler's
actual vocabulary size and the numbers produced by the MacArthur CDI?  I'm
particularly interested in the question of how this difference might vary
from category to category.  For example, if the CDI captured only 50% of some
todder's common noun vocabulary but 80% of other words, a naive approach
like dividing the CDI common noun count by the CDI total word count would
underestimate the percentage of common nouns in the toddler's lexicon.

An extreme case of this would be proper nouns, which are scarcely on the
CDI at all.  Can anyone point me at estimates of the typical size of
toddler proper noun vocabularies (people, animals, cartoon characters,
books, songs, etc)?

Many thanks,

Margaret Fleck



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Margaret M. Fleck
    510-378-3075
    margaretmfleck at yahoo.com