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# 9.12: Lesson Twelve

Created by: CK-12

## More About the Prefix Ex-

1. In the words you have worked with so far the prefix ex- has always been spelled <ex>. But when ex- is added to a stem that starts with an <f>, the <x> assimilates to an <f>. In many other words the <x> is deleted and nothing is put in its place. This partial assimilation makes pronunciation easier.

Each of the following words begins with some form of the prefix ex-. Analyze each one into its prefix and stem. Show any assimilation that take place:

Word = Prefix + Stem
exclaiming = +
effective = +
editor = +
exhibited = +
elaborate = +
emerging = +
emotional = +
evidently = +
efficient = +
elections = +
enormous = +
excitement = +

2. Usually ex- assimilates only partially, by just deleting the <x>. It often does so with stems with which other prefixes assimilate fully to make a double consonant. So though we have elect with a single <l>, we have collect with <ll> because of full assimilation:

$elect & = e{\cancel{x}} + lect, \ \text{with} <\text{l}> \\collect & = co{\cancel{m}} + l + lect, \ \text{with} <\text{ll}>.$

Here are some other pairs like elect and collect. In each pair the first word contains an assimilated form of the prefix ex-. The second word contains a different prefix. Both words in each pair contain the same stem. Analyze each word into its prefix plus stem. Then underline any double consonants:

Word = Prefix + Stem
election = e$\cancel{x}$ + lection
collection = co$\cancel{m}$ + l + lection
emotion = +
commotion = +
immigrate = +
edicts = +
eminent = +
imminent = +
erected = +
corrected = +
elapsed = +
collapsed = +
edition = +
eroding = +
corroding = +

3. Usually when ex- is added to a stem that starts with $<\text{s}>$, an unusual assimilation takes place. For example, in the word expect the base is actually spect, the same base that is in inspect and respect. But in expect the $<\text{s}>$ is deleted: ex + $\cancel{s}$pect. All of the following words have this same unusual assimilation. Analyze each one into prefix plus stem, showing the $<\text{s}>$-deletion:

Word = Prefix + Stem
expect = ex + $\cancel{\text{s}}$pect
exist = +
expire = +
executive = +
exertion = +
extinct = +
extant = +
extinguisher = +
exude = +

## Categories:

1 , 2 , 3 , 4 , 5

## Date Created:

Feb 23, 2012

Apr 29, 2014
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