Mental Bookmark: Prefixes for Vocabulary Development

Shaywitz, Sally, Overcoming Dyslexia: A New and Complete Science-Based Program for Reading Problems at Any Level, New York: Knopf, 2003.
HELPING YOUR CHILD BECOME A READER: Helping Your Child Become a Skilled Reader
pp. 239-240

Just twenty prefixes account for 97 percent of all words with prefixes found in English schoolbooks, and nine of these prefixes account for 75 percent of all prefixed words. Here are the most common ones:

RANK	PREFIX	MEANING	%AGE of prefixed words
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-	in	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
All others			4