A featural alphabet is an alphabet wherein the shapes of the letters are not arbitrary, but encode phonological features of the phonemes they represent. Examples include the following:
SignWriting (a script for writing the world\'s sign languages; technically this is not an alphabet)
SpeechWriting (Mundbildschrift: a script for writing mouth movements of voiced words)
Other alphabets may have limited featural elements. For example, the Fraser alphabet used for Lisu rotates the letters for the tenuis consonants P /p/, T /t/, F /ts/, C /tʃ/, and K /k/ 180° to indicate aspiration. The International Phonetic Alphabet also has some featural elements, for example in the hooks and tails that are characteristic of implosives, ɓ ɗ ʄ ɠ ʛ, and retroflex consonants, ʈ ɖ ʂ ʐ ɳ ɻ ɽ ɭ. The IPA diacritics are also featural.
