Mac Keyboard Layout

The Mac support multi-language input both in hardware and software.

Hardware
When ordering Apple Macintosh hardware, you are given a choice of keyboard layout. This affects the configuration of the keys on your keyboard. Apple Knowledge Base HT2841 lists 32 different keyboard layouts.

In the Netherlands, Apple ships three similar keyboards:
 * US
 * International English
 * Dutch

The US keyboard is based on the ANSI standard:



The International English and Dutch keyboards are based on the ISO 9995 standard:



The only difference between the US and International English keyboard is the tick (`) / tilde (~) key and the paragraph (§) key. On the US keyboard, the tick/tilde key is located left of the "1" key, while on the International English keyboard, the tick/tilde key is located left of the "Z" key, by claiming part of the shift key to make room for this key. The key left of the "1" key on the International English is a Paragraph (§) / Plus-minus (±) key. This key does not exist on the US keyboard.

The only difference between the International English and Dutch keyboard is the Euro symbol as the second alternative to the "2" key:



Other countries have more profound differences.

More information

 * How to identify keyboard localizations (Apple Knowledge Base HT2841).
 * Wikipedia on Keyboard Layouts

Hardware Recognition
If a generic keyboard is plugged in to the Mac, the user is asked to press the keys next to the shift keys for detection of the type of keyboard. Users may see a dialog choosing a layout of ASCI, ISO 9995, or Japanese. This preference is retained in the file /Library/Preferences/com.apple.keyboardtype.plist after the keyboard is unplugged and plugged back in.

Software
The keyboard layout software translates a key press to a character on screen. Mac OS X offers 139 software keyboard layouts.

I'll list three examples here, the US, US International and ABC-Extended (previously: US Extended) keyboard.

The US keyboard and US International keyboards are very similar. The difference is that the US International turns the tick (`) and single quote (') keys into modifier keys (for grave accent and acute accent). The US keyboard only does this when the alt key is pressed. The US International always does this.

The difference between the US and extended keyboard is more profound. The extended keyboard allows for much more modifier keys to create ligatures, as can be seen in the table:

The extended keyboard more closely follows the spirit of the ISO 9995-3:2009 keyboard layout (although the location of the modifier keys is different). Most layouts (such as Dutch or British layout) are based on the regular US layout with only a limited number of modifiers keys. The difference between Dutch and US or between British and US keyboard is minor. In the Dutch keyboard, the euro (€) sign is accessible by alt-2 instead of alt-shift-2. In the British keyboard, the pound sign is layout is accessible by shift-3 instead of alt-3.

Applications
The two Mac OS X applications to edit a keyboard layout are:


 * Karabiner, a powerful and stable keyboard customizer for Mac OS X.
 * Ukelele, a Unicode Keyboard Layout Editor for Mac OS X.