Below is a table containing the words that make all the difference in a competent user of English, because according to James I. Brown, Professor of Rhetoric at the University of Minnesota, in his book Programmed Vocabulary, they contain the twenty most useful prefixes and the fourteen most important roots in our language. These constituent parts make up over 14,000 words in a collegiate dictionary size or close to an estimated 100,000 words in an unabridged dictionary. In other words, you should know these words and understand why they mean what they mean since doing so will grant you a superior vocabulary. Click it for a slightly larger view.