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Difficulty Level: At Grade Created by: CK-12

1. Many of our words come from Latin, the language spoken by the ancient Romans. Many of these old Latin words contain a prefix that was at first spelled <ad> and meant “to, toward.”

In some words the [d] in the prefix ad- has changed to a different sound, and the <d> has been replaced by a different letter.

We can divide adventure into its prefix and stem like this: ad + venture.

And we could divide appoint into its prefix and stem like this: ap + point. But the <ap> in appoint is really a changed form of the prefix ad-. The <d> has been replaced with a \begin{align*}<\mathrm{p}>\end{align*} :a\begin{align*}\cancel{d}\end{align*} + p + point.

The <d> in ad- is deleted, and a \begin{align*}<\mathrm{p}>\end{align*} is put in its place.

In adventure, we add the prefix and the stem together by simple addition. But in the word appoint we replace the <d> in the prefix with a \begin{align*}<\mathrm{p}>\end{align*}.

2. Each of the following words begins with some form of the prefix ad-. Sometimes the <d> has stayed <d>. Sometimes it has been replaced by another letter. Analyze each word into its prefix and its stem the way we did with adventure and appoint. If the <d> has been replaced with a different letter, show that change in your analysis.

Words = Prefix + Stem
appoint = a\begin{align*}\cancel{d}\end{align*} + p; + point
approve = a\begin{align*}\cancel{d}\end{align*} + p; + prove
apply = a\begin{align*}\cancel{d}\end{align*}+ p + ply
acclaim = a\begin{align*}\cancel{d}\end{align*} + c + claim
account = a\begin{align*}\cancel{d}\end{align*} + c + count
attack = a\begin{align*}\cancel{d}\end{align*} + t + tack
allow = a\begin{align*}\cancel{d}\end{align*} + l + low
assist = a\begin{align*}\cancel{d}\end{align*} + s + sist
attend = a\begin{align*}\cancel{d}\end{align*} + t + tend

3. Now sort the words in the Words column into these two groups:

Words in which the <d> in
stayed <d>: was replaced with a different letter:

Word Venn. In circle A put only words that contain some form of the prefix ad-. In circle B put only words that contain the prefix re-. In circle C put only words that contain the prefix un-.

\begin{align*}& \text{appoint}\surd && \text{readjust}\surd && \text{unapproved}\surd\\ & \text{unreceptive}\surd && \text{unreassuring}\surd && \text{unclaimed}\surd\\ & \text{unjust}\surd && \text{unassisted}\surd && \text{unregretted}\surd\\ & \text{realize}\surd && \text{reclaimed}\surd && \text{universe}\surd\\ & \text{acclaimed}\surd && \text{readmitted}\surd && \text{receiving}\surd\end{align*}

Teaching Notes.

Item 1. This lesson is the second example of the third of the three kinds of change that can preempt the Rule of Simple Addition: replacement. The first example was the <y>-to-\begin{align*}<\mathrm{i}>\end{align*} replacement. The students studied the first two kinds of changes, addition and deletion, in their work with twinning and final <e> deletion. The replacement of the <d> in ad- with some other consonant is due to a process called assimilation, as the students will learn in the next lesson.

The main objective of the work with assimilated prefixes is to help students recognize the various forms a prefix like ad- takes and to understand when and why the changes in form occur. This recognition can help the students see a unity - and thus a simplification - in the language where to the uninformed eye there would be just meaningless complexity with no unity or pattern at all. At a more particular and practical level, work with assimilated prefixes like ad- can help with two spellling problems:

First, it can help students anticipate and remember the double consonants in words like apply and attack. We often use double consonants to mark stressed short vowels in VCC strings, but we seldom have double consonants that are preceded by unstressed schwa. The vowels in assimilated prefixes are the major case where schwa occurs right before a double consonant. Just as the twinning rule explains the presence of double consonants at the end of many stems, the assimilation of prefixes explains their presence at the front.

The second way work with assimilated prefixes can help is with the schwa itself: If students can identify the prefixes in words, they are in a better position to know which vowel letter spells the schwa that is normal in those prefixes. For instance, the schwa heard in the many forms of ad- is always going to be spelled \begin{align*}<\mathrm{a}>\end{align*}.

Item 2. Students may ask about the stems and bases in this table. Since much of our concern in this program is to help students see connections and patterns among words, questions such as “Is the point in appoint the same as the point when you point your finger at someone?” are valuable questions indeed. The prefix ad- means, literally, “to, towards.” In most of the old Latin words in which it appears, ad-'s meaning can be hard to make out. In some cases, though, a meaning can be retrieved: Since adverbs modify verbs, they are, in a sense, directed towards verbs ad+verb. In advertise the base vert means “turn,” and when you advertise, you do in a way try to turn someone towards the thing you are advertising. And you can feel a sense of “to, towards” in words like acclaim and appoint, the latter of which does contain the free base point.

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