Skip Navigation

9.5: The Prefix Com- and Partial Assimilation

Difficulty Level: At Grade Created by: CK-12
Turn In

The Prefix Com- and Partial Assimilation

1. In an earlier lesson we saw that sometimes the <n> in the prefix in- changes to an <m> even though the first letter of the stem is not an <m>. An example is the word impression: i\begin{align*}\cancel{n}\end{align*} + m + pression. This is called partial assimilation. The prefix com- does a similar thing:

In most of the words with com- the <m> changes to an <n>, even when the stem does not start with an <n>. This partial assimilation of <m> to <n> still makes the word easier to say.

2. The first three letters in each of the following words are some form of com-. Sometimes it has assimilated partially by changing <m> to <n>, and sometimes it has not. Analyze each word to show what happened when com- was added to the stem in that word:

Word = Prefix + Stem
consist = co\begin{align*}\cancel{m}\end{align*} + n + sist
conduct = co\begin{align*}\cancel{m}\end{align*} + n + duct
conversation = co\begin{align*}\cancel{m}\end{align*} + n + versation
commission = com + mission
compare = com + pare
confidence = co\begin{align*}\cancel{m}\end{align*} + n + fidence
composition = com + position
consent = co\begin{align*}\cancel{m}\end{align*} + n + sent
confession = co\begin{align*}\cancel{m}\end{align*} + n + fession
content = co\begin{align*}\cancel{m}\end{align*} + n + tent
commerce = com + merce
congress = co\begin{align*}\cancel{m}\end{align*} + n + gress
conceal = co\begin{align*}\cancel{m}\end{align*} + n + ceal
confront = co\begin{align*}\cancel{m}\end{align*} + n + front
continue = co\begin{align*}\cancel{m}\end{align*} + n + tinue

3. Now sort the fifteen words into these two groups:

Words in which the <m>...
assimilated partially did not assimilate at all
consist consent conceal commission
conduct confession confront compare
conversation content continue compostion
confidence congress commerece

Word Change. Make the changes called for by the instructions and fill in the blank in the final sentence:

Instructions Words
1. Write the word college. 1. college
2. Change the fourth consonant in the word to the second consonant in the alphabet. Then change the second <e> in the word to the letter that comes between \begin{align*}<\mathrm{s}>\end{align*} and \begin{align*}<\mathrm{u}>\end{align*} in the alphabet. 2. collect
3. Change the third and fourth letters in the word to the letters that come two places after them in the alphabet. 3. connect
4. Change the third and fourth letters in the word to the letters that come four places after them in the alphabet. 4. correct
5. Change the second consonant in the word to the letter that comes between <m> and <o> in the alphabet. Then change the third consonant in the word to the third consonant in the alphabet. And then change the <e> to \begin{align*}<\mathrm{u}>\end{align*}. 5. conduct
6. Change the base of the word to <sist>. 6. consist
7. Change the second vowel in the word to the second vowel in the alphabet. Change the fourth consonant in the word to <n>. 7. consent

If you followed the instructions just right, your solution is \begin{align*}\frac{\mathrm{correct}}{\mathrm{Word} \ \# 4}\end{align*}.

Teaching Notes.

Item 1. The partial assimilation of com- to con- eases pronunciation once again by moving the points of articulation closer together. Notice that while [m] is pronounced at the two lips, sounds like [d], [s], and [t], as in conduct, consent, and content, are all pronounced with the tongue near the back of the teeth, which is also the position for pronouncing [n]. Thus [nd], [ns], [nt] are easier sequences to pronounce than would be [md], [ms], and [mt].

Notice, too, that [f] falls between the points of articulation for [m] and [n]. The sound [f] is pronounced with the lower lip touching the upper front teeth (thus [f] is called a labiodental sound). It is apparently this “tweener” state that causes the lack of assimilation in words like comfrey, comfit, and most importantly comfort. In most words with stems that start with [f] (or its voiced partner [v]) the [m] assimilates to [n], as in confidence and conversation, but in comfrey, comfit, and comfort there is no assimilation.

Item 2. Concerning conversation: The evolution of converse from the root meaning "to turn with” to the modern meaning “to speak informally with" was a long one. The following description is from the OED: The Latin convers\begin{align*}\bar {a}\end{align*}re, originally “to turn to and fro,” came to mean “to turn oneself about, to move to and fro, to pass one's life, dwell, abide, live somewhere, keep company with.” In French this became converser, which originally meant “to pass one's life, live, dwell in or with.” but developed the meaning “to exchange words with.” French converser was the source of English converse and thus conversation. To me there seems to be a somewhat similar line of development in the semantically related words turn and return.

Notes/Highlights Having trouble? Report an issue.

Color Highlighted Text Notes
Show More

Image Attributions

Show Hide Details
1 , 2 , 3 , 4 , 5
Date Created:
Feb 23, 2012
Last Modified:
Jul 07, 2015
Files can only be attached to the latest version of section
Please wait...
Please wait...
Image Detail
Sizes: Medium | Original