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# 7.7: The Diphthong [oi]

Difficulty Level: At Grade Created by: CK-12

## The Diphthong [oi]

1. You can hear the diphthong [oi] in spoil and joy. It sounds like a short <o> run together with a short <i>\begin{align*}<\mathrm{i}>\end{align*}. The sound [oi] is spelled either <oi> or <oy>. Underline the letters that spell [oi] in each of the following words:

enj\underline{oy}j\underline{oy}s\underline{oi}lt\underline{oy}ingm\underline{oi}stenp\underline{oi}ntedb\underline{oi}lc\underline{oi}nt\underline{oi}letr\underline{oy}alv\underline{oy}agev\underline{oi}ces\underline{oi}ledl\underline{oy}altyp\underline{oi}sondestr\underline{oy}\begin{align*}& \text{enj\underline{oy}} && \text{m\underline{oi}sten} && \text{t\underline{oi}let} && \text{s\underline{oi}led}\\ & \text{j\underline{oy}s} && \text{p\underline{oi}nted} && \text{r\underline{oy}al} && \text{l\underline{oy}alty}\\ & \text{\underline{oi}l} && \text{b\underline{oi}l} && \text{v\underline{oy}age} && \text{p\underline{oi}son}\\ & \text{t\underline{oy}ing} && \text{c\underline{oi}n} && \text{v\underline{oi}ce} && \text{destr\underline{oy}}\end{align*}

2. Sort the sixteen words into these two groups:

Words in which [oi] is spelled...
<oi> <oy>
oil toilet enjoy voyage
moisten voice joys loyalty
pointed soiled toying destroy
boil poison royal
coin

3. Here are some words that contain the diphthong [oi]. They have been analyzed into their elements. Look at each carefully and notice whether the [oi] sound is at the front, in the middle, or at the end of its element:

en+joy+mentjoy+ful+lyboilboy+‘sun+soil+edjoin+ingchoice+soil+ycoinvoice+less+lytoil+etroy+alvoy+agepoint+lessloy+al+tyap+point+mentde+stroy+erspoil+eda+voidpoison\begin{align*}& \text{en+joy+ment} && \text{join+ing} && \text{toil+et} && \text{ap+point+ment}\\ & \text{joy+ful+ly} && \text{choice+s} && \text{roy+al} && \text{de+stroy+er}\\ & \text{boil} && \text{oil+y} && \text{voy+age} && \text{spoil+ed}\\ & \text{boy+‘s} && \text{coin} && \text{point+less} && \text{a+void}\\ & \text{un+soil+ed} && \text{voice+less+ly} && \text{loy+al+ty} && \text{poison}\end{align*}

4. Now sort the twenty words into the matrix, as we have done with enjoyment.

Words with [oi]...
at the end of the element not at the end of the element

Words with [oi]

spelled <oy>

enjoyment

joyfully

boy's

royal

voyage

loyalty

destroyer

Words with [oi]

spelled <oi>

boil

unsoiled

joining

choices

oily

coin

voicelessly

toilet

pointless

appointment

spoiled

avoid

poison

5. How Do You Spell [oi]? When the sound [oi] comes at the very end of an element, it is spelled <oy>; everywhere else it is spelled <oi>.

Word Venn. In circle A put only words that contain the sound [ou˙]\begin{align*}[\mathrm{o}\dot{\mathrm{u}}]\end{align*}. In circle B\begin{align*}B\end{align*} put only words that contain the sound [oi]. In circle C put only words that contain the sound [z]:

amountsoutpointedappointmentscowboysvowelsvoicesallowancespecializebicyclistpuresttoiletshouseboycoinsjournalsthousands\begin{align*}& \text{amounts}\surd && \text{vowels}\surd && \text{bicyclist}\surd && \text{coins}\surd\\ & \text{outpointed}\surd && \text{voices}\surd && \text{purest}\surd && \text{journals}\surd\\ & \text{appointments}\surd && \text{allowance}\surd && \text{toilets}\surd && \text{thousands}\surd\\ & \text{cowboys}\surd && \text{specialize}\surd && \text{houseboy}\surd\end{align*}

Teaching Notes.

Item 3. The free base toil originally meant “web, weaving.” It is our free base toil “net, trap,” as in “They were caught in the wicked villain's toils.” The evolution of our current sense of toilet is complex: Originally toilet meant “little cloth”; it was used to refer to the cloth used to keep toilet articles clean. Then it transferred to the table on which the articles were kept, then to the act of adorning oneself, then to the room in which the toilet took place, then to our current senses. The base roy “king” occurs also in royalty viceroy. Folk etymology has taken corduroy to mean “cord, or cloth, of the king,” though corduroy has nothing to do with France or French.

Item 5. That is a good rule for spelling [oi]. The only common words that don't fit it are oyster and gargoyle. Oyster, with the <oy> spelling at the front rather than the end of the element, was earlier spelled <oister>, which did fit the rule. We don't really know why the spelling was changed. Gargoyle, with the <oy> spelling in the middle of the element, was once spelled <oi> (and several other ways!). Again, we don't know why the <oy> spelling became standard.

For more on the history and spelling of [oi], see AES, pp. 301-03.

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