Defective script

In graphemics, a defective script is a writing system that does not represent all the phonemic distinctions of a language. This means that the concept is always relative to a given language. Taking the Latin alphabet used in Italian orthography as an example, the Italian language has seven vowels, but the alphabet has only five vowel letters to represent them; in general, the difference between the phonemes close /e, o/ and open /ɛ, ɔ/ is simply ignored, though stress marks, if used, may distinguish them. Among the Italian consonants, both /s/ and /z/ are written ⟨s⟩, and both /t͡s/ and /d͡z/ are written ⟨z⟩; stress and hiatus are also not reliably distinguished.

Ancient examples of defective script

Such shortcomings are not uncommon. The Greek alphabet was defective during its early history. Ancient Greek had distinctive vowel length: five short vowels, /i e a o u/, and seven long vowels, /iː eː ɛː aː ɔː oː uː/. When the Phoenician alphabet was adapted to Greek, the names of five letters were pronounced by the Greeks with initial consonants made silent, and were then used acrophonically to represent vowels. These were alpha, e (later called e psilon), iota, o (later called o micron), and u (later called u psilon) – <α, ε, ι, ο, υ> – five letters for twelve vowel sounds. (The lost initial consonants were /ʔ, h, j, ʕ, w/.) Later the [h] (from /ħ/) dropped out from the Eastern Greek dialects, and the letter heta (now pronounced eta) became available; it was used for /ɛː/.