The Mac operating system provides support for special characters found in many different languages. Known as a macron, many languages including Latin, Japanese, Chinese, Korean and Old English require the symbol over certain letters. With Mac OS X Mavericks, you can add a macron over a letter using the Special Characters palette without needing to enable any advanced language settings. If you know which characters support macrons, you can also enter the letters into supported documents using a simple keystroke.
Place your cursor at the position in the document where you want to insert your macron.
Press and hold the letter you want to use for about two seconds. A list of diacritic symbols displays with the letter you selected. Click the letter that shows a macron. For example, press and hold the "A" key to show the letter A with a macron over it.
Click the "Edit" menu and select "Special Characters..." from the drop-down menu, if the letter you want to use doesn't display when holding down the key. Type "macron" into the Search field and double-click the letter you want to use to insert it into the document.
You can only use a macron with a vowel.