Dead key

For example, if a keyboard mapping (such as US international) has a dead key for the circumflex, ^, the character â can be generated by first pressing ^ and then a.

To use a single diacritic, such as the acute accent, with multiple foundation characters (such as á, é, í, ó, ú) the decision was made to create a new character, the acute accent or diacritic ´, which did not exist in typesetting as of that date.

Due to a change in the mechanism, striking the key containing the accent did not advance the paper (the key was "dead" or non-spacing), meaning it could be followed by any character that was to appear under the acute accent, producing an overstruck character.

Each combination of a diacritic and a base letter must be specified in the character set and must be supported by the computer font in use.

[a] Unicode encoded over one hundred precomposed characters with two diacritics, for use in Latin script for Vietnamese and a number of other languages.

For convenience, they are generated on most keyboards supporting them, by pressing the two corresponding deadkeys in any order, followed by the letter key.

If this flag is set to its default value zero, the composed character is inserted; if it is set to one, the composed character code is handled as another diacritic code like those due to dead key presses, and occurs typically as a second argument in other dead list entries.

This may be performed either with proprietary keyboard editing software,[3] or with driver development kits.