The final consonant of a Latin prefix may change because of the beginning letter of the roots. The change is due to “euphony” meaning to sound better. Because the prefixes change to match or to sound better with the first letter of the root word, these prefixes are sometimes called “chameleon” prefixes. Another term used by linguists is “assimilated prefixes.” The prefix in-, meaning in or not, changes to il- before roots beginning with l as in illustrate and illegal. The in- changes to ir- before roots beginning with r as in irregular and irreligious, and to im- before roots beginning with m, b, or p as in immune, imbalance, and importing. Students will hear how difficult it is to say “inlegal” or “inregular” or “immune.” (See handout for summary of changes.)

The prefix con-, meaning together or with, changes to col-, cor-, or com- in similar circumstances as in collide, corrected, and commit, combine, and compute. The prefix ad-, meaning to or toward, has many variants such as ac- in accept, ag- in aggressive, al- in alleviate, an- in announcement, ap- in apparent, as- in assertion, and at- in attentive. The prefix sub-, meaning under or below, changes to suc- in succession, suf- in sufferance, sug- in suggestion, sup- in supportive, and sus (before p or t) in suspend and sustain. In addition, variants occur for ob- (down, against) such as oc-, of-, and op- in occur, offer, and opposition.

Once students know the roots and affixes, words containing the chameleon prefixes are not difficult to read. Spelling the words, however, is more difficult as the final consonant of the prefix and similar beginning consonant of the root aren’t always both heard. Students need numerous opportunities to read and spell words containing these prefixes. Provide students with handout summarizing the chameleon prefixes. Have lists of words prepared for them to read, and then dictate words containing these prefixes.