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Word Roots are a Part of History. "Histories Make Men Wise" -- Bacon.

Learning English Roots

Part 1: Most Frequently Used English Prefixes



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There are 23 most frequently used English prefixes in the table below.
We have a dictionary of 84099 unique English words. To figure out how the prefixes are applied to English words and their frequencies, we create computer programs to go to the internet to scrub the following three dictionaries: American Heritage Dictionary, Collins Dictionary, and Random House Kernerman Webster's College Dictionary.
There are 7907 unique basic words to which the prefixes are applied, one basic word may have more than one prefixes applied. Once a prefix is correctly applied to a basic word in the dictionary, the basic word becomes another word in the dictionary.
The total nubmer of English words that have the prefixes applied is 10325. This means that the prefixes in the table below can effectively expand some words into some other words in the Dictionary. The expansion ratio is:
10325/7907 = 1.31
which means that if you already know the meanings of 100 words, by applying the prefixes in the table below, then you can instantly expand your vocabulary by up to 1.31 times on average! Considering that you already know the 100 words, now the size of your vocabulary is 100 + 100 * 1.31 = 231
which means that the grand expansion ratio of your vocabulary by just learning these prefixes is: 2.31 times on average! How effective this is!
However if you know no words, then your grand expansion ratio is still zero.
The first step to correct dissect an English word is to correct recognize the prefix and suffix in it. More useful prefixes and suffixes are given in Part 5 and Part 6.


Note 1: Based on the frequency in the table, you will see that the top five prefixes that are used most frequently are: un-, re-, in-, de- and dis-. (in- also includes il-, im-, and ir)

Note 2: in-, im-, il-, and ir- are equivalent. in- is usually assimilated to il- before l; before r to ir-; and before b, m, and p to im-. Other examples of assimilation: sample where s is actually ex-; spend where s is actually ex-; sport where s is actually dis-. Assimilation is just for easy pronunciation.
A great video about phonetic changed CrazyEnglish Phonetic Change

Note 3: Mankind invents a lot of prefixes or suffixes to describe not or negation: non-, un-, in-, im-, il-, ir-, anti-, de-, dis-, -less

Prefix Meaning Example Words Frequency Used with Greek Root Used with Latin Root
anti- against antisocial,
antifreeze
98 anti- anti-
de- opposite defrost,
decompress
1110 de-
dis- not,
opposite of
disagree,
dissimilar
820 dis- dis-
em- cause to embrace 133 em- em-
en- cause to encode,
endear
453 en- en-
fore- before forecast,
forewarn
133
il- not illegal,
illogical
45 il-
im- not impossible,
impolite
357 im-
in- in infield,
infiltrate
1004 in-
in- not injustice 1004 in-
inter- between interact,
international
259 inter-
ir- not irreparable 97 ir-
mid- middle midway,
midsummer
50
mis- wrongly misfire,
misconduct
365 mis- mis-
non- not nonsense,
nonexistent
33 non-
over- over overlook,
overcharge
563
pre- before prefix,
prehistoric
319 pre-
re- again,
back
return 1878 re-
semi- half semicircle,
semiannual
30 semi-
sub- under submarine,
subsoil
236 sub-
super- above superstar,
superimpose
98 super-
trans- across transport,
transoceanic
127 trans-
un- not unfriendly,
unhappy
1885 un-
under- under undersea 232


For how to apply these prefixes, please see: Part 4: An Algorithm for the Conversions of Parts of Speech and Negation of English Words