This list is from Overcoming Dyslexia, by Sally Shaywitz, MD. A noted researcher in neuroscience and a pediatrician, Dr Shaywitz is professor of pediatrics and codirector of the Yale Center for the Study of Learning and Attention. She is also a member of the Institute of Medicine of the National Academy of Sciences. She hopes her book will be a “trusted source you can turn to for information, for advice, for guidance and for explanation.”. If your child knows these twenty prefixes, he will be able to add many words to his vocabulary. They account for 97 percent of all words with prefixes!

  1. Un- (not) 26%
  2. Re- (again) 14%
  3. In-, im-, il-, ir- (not) 11%
  4. Dis- (not) 7%
  5. En-, em- (put into) 4%
  6. Non- (not) 4%
  7. In-, im- (put into) 3%
  8. Over- (excessive) 3%
  9. Mis- (bad) 3%
  10. Sub- (below) 3%
  11. Pre- (before) 3%
  12. Inter- (between) 3%
  13. Fore- (earlier) 3%
  14. De- (reverse) 2%
  15. Trans- (across) 2%
  16. Super- (above) 1%
  17. Semi- (half) 1%
  18. Anti- (opposite) 1%
  19. Mid- (middle) 1%
  20. Under- (too little) 1%
  21. All others 4%