Name _______________________________________

Lesson 13   The assimilated prefix ad


de + celerate =decelerate ex + cuse = excuse
ad + celerate = accelerate ad + cuse = accuse
re + locate = relocate in + tention = intention
ad + locate = allocate ad + tention = attention
   
pro + gression = progression pro + nounce = pronounce
ad + gression = aggression ad + nounce = announce
   
de + rive = derive re + sent = resent
ad + rive = arrive ad + sent = assent
   
re + sume = resume com + prehend = comprehend
ad + sume = assume ad + prehend = apprehend
   


1. Do the words in each pair have the same root? _____
Do they have the same prefix? _____
   
2. Look at the first word in each pair. Does the spelling of the prefix change when it is added to form the word? _____
   
3. What prefix is added to form the second word in each pair? _____
How is the prefix spelled when it is joined to a root that begins
with a c? _____ with an l? ____ with a g? _____ with an r? _____
with an s? _____ with a t? _____ with an n? _____ with a p? _____
   
4. Is it easier to pronounce adcelerate or accelerate? __________
Adrive or arrive? __________

Lesson Generalization

When the last letter of a prefix changes to match the first letter of a root, the prefix is said to be assimilated.

ad + similat + ed = assimilated
(to) (same or similar) ( made similar to)

The prefix ad is assimilated more often than any other prefix. It also causes more double-consonant spelling problems than any other prefix.

Mnemonic device: Remember that one of the double consonants is really the Mad Ad in disguise.





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