A language marks the plurality of a noun by adding a prefix to it.  Consider, for example, the Anindilyakwa construction <i><b>wirr</b>-iyikwayiwa</i> '<b>PL</b>-child' meaning "children."

<br><br><b>Reference</b><br>
Dryer, Matthew S.. 2008. Coding of Nominal Plurality.
In Haspelmath et al (2008), chapter 33. Available online at <a href="http://wals.info/feature/33">
http://wals.info/feature/33</a href>.
