Name _______________________________________

Lesson 21  More assimilated prefixes

ad + ford = afford com + respondent = correspondent
ad + fliction = affliction com + rupt = corrupt
ad + firmative = affirmative in + responsible = irresponsible
ad + fection = affection in + rigation = irrigation
dis + ficult = difficult in + resistible = irresistible
sub + fered = suffered com + lision = collision
sub + focate = suffocate com + lapse = collapse
sub + ficient = sufficient in + luminate = illuminate
ob + ficial = official in + legible = illegible
ob + fered = offered in + literate = illiterate

1. When the prefixes in the first column are joined to roots that begin with the letter f, how does the spelling of each prefix change? _____ becomes _____, _____ becomes _____, _____ becomes _____, and _____ becomes _____.
2. The roots in the second column begin with the letter r or the letter l.
When the prefixes com and in are joined to roots that being with the letter r, com is spelled _____, and in is spelled _____. When com and in are joined to the letter l, com is spelled _____, and in is spelled _____.
3. In all of the prefixes, which letter changes to match the first letter of the root? ______________________________________________
4. What common spelling problem might occur in all of the list words because the prefixes are assimilated into the roots?______________________________________________

Lesson Generalization

If prefixes were always added directly to a base word or root, some consonant combinations would be difficult to pronounce:

adford   disficult   subfocate   comrespond  comlapse

Assimilated prefixes solve pronunciation problems but cause spelling problems. Double consonants result when the last letter of the prefix changes to match the first letter of the root.

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