The top 1,000 vocabulary words have been carefully chosen to represent difficult but common words that appear in everyday academic and business writing. These words are also the most likely to appear on the SAT, ACT, GRE, and ToEFL.
Marvin list of 333 alphabetized preschool core words - Preschoolers' Vocabulary Arranged Alphabetically - REFERENCE: Marvin, C. A., Beukelman, D. R., Bilyeu, D. (1994). Vocabulary-use patterns in preschool children: Effects of context and time sampling. Augmentative and Alternative Communication, 10, 224-236. The words on this list are the most frequently occurring words of preschool children in the study by Marvin, Beukelman, and Bilyeu.