deadkey

A dead key is a key on a keyboard that does not produce a character by itself but modifies the character produced by the next key press. It is used to enter characters with diacritics or other marks that are not available on a single keystroke, enabling input of accented letters, umlauts, tildes, and similar diacritics across many languages.

When a dead key is pressed, the keyboard enters a special input state and waits for the following key. The combination typically yields a precomposed character (for example é, ö, ñ) if such a character exists in the character set. If a precomposed form is not available, the system may emit a base character followed by a combining diacritic, creating a visually composite symbol. Some keyboard layouts also support stacking more than one dead key to produce letters with multiple diacritics.

Examples of common dead keys include accents such as acute (´), grave (`), circumflex (^), tilde (~), diaeresis (¨), and ring (˚). For instance, pressing the acute dead key followed by e typically yields é, while the tilde dead key followed by n yields ñ. Different keyboard layouts and input methods may implement dead keys differently, and some environments use combining characters rather than precomposed forms.

Dead keys are widely supported across operating systems and input methods (Windows, macOS, Linux, various mobile keyboards). They remain a practical solution for typing in many languages without requiring a dedicated key for every diacritic. Some users prefer direct composition or alternative layouts, but dead keys continue to facilitate efficient diacritic input in multilingual contexts.