Name _______________________________________

Lesson 20   The prefixes com and in

com + gressional = congressional in + tuition = intuition
com + servative = conservative in + sulation = insulation
com + notation = connotation in + nocent = innocent
con + mentator = commentator in + munity = immunity
com + mute = commute in + mortality = immortality
com + mercial = commercial in + mediately = immediately
com + petition = competition in + patient = impatient
com + puter = computer in + postor = impostor
com + promise = compromise in + peached = impeached
com + bustion = combustion in + bedded = imbedded

A prefix may be spelled in several different ways.

1. Look at the first three words in each column. Are the prefixes com and in spelled with an n or an m when they are added to form these words? _____

Why do the words connotation and innocent have double consonants? ______________________________________________
2. Look at the remaining words in each column. How is the prefix com spelled when it is added to roots that being with m, p, or b? _____

How is the prefix in spelled when it is added to words or roots that begin with m, p, or b? _____

Lesson Generalization

The prefixes com and in follow the same spelling pattern. Both are spelled with an n before most letters of the alphabet. Both are spelled with an m before roots or words that begin with the letters m, p, or b. They are spelled this way to make more compatible combinations that are easier to pronounce.

Say inmediately and immediately. Say conmute and commute.
Mnemonic device: Remember common compatible combinations.

Double consonants often result from joining prefixes and roots. Remember that one consonant belongs to the prefix, and one belongs to the root.

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