Accessing Special Characters and Foreign Languages on Mac Keyboards
Macs let you input text in a wide variety of languages. On the menu bar at the top right, you should see a little national flag, corresponding to the keyboard's language (you made this selection during the startup process). For example, stars and stripes appear for the U.S. keyboard. If you click this flag, a menu of options appears. Select Show Character Palette. You can browse through the thousands of characters available on OS X. Click the small triangles next to Character Info and Font Variation to discover the name of each character and which fonts contain it.
You can add keyboard layouts for other languages from the Apple menu by choosing System Preferences→International and then choosing Input Menu. Each language you check shows up as a menu option under the flag icon on the menu bar.
Select Show Keyboard Viewer from the flag menu, and a small keyboard corresponding to the language you chose appears. You can enter characters with it by clicking its buttons.