text: In abjads derived from the Aramaic alphabet, notably Arabic and Hebrew, long vowels are written with consonant letters (mostly approximant consonant letters) in a process called mater lectionis e.g. in Modern Arabic the long vowel  is represented by the letter ا (Alif), the vowels  and  are represented by و (wāw), and the vowels  and  are represented by ي (yāʼ), while short vowels are typically omitted entirely. Most of these scripts also have optional diacritics that can be used to mark short vowels when needed.
  In South-Asian abugidas, such as Devanagari or the Thai alphabet, there are different vowel signs for short and long vowels.
  Ancient Greek also had distinct vowel signs, but only for some long vowels; the vowel letters  (eta) and  (omega) originally represented long forms of the vowels represented by the letters  (epsilon, literally "bare e") and ο (omicron – literally "small o", by contrast with omega or "large o"). The other vowel letters of Ancient Greek,  (alpha),  (iota) and  (upsilon), could represent either short or long vowel phones.
  Japanese phonology:
  In the hiragana syllabary, long vowels are usually indicated by adding a vowel character after. For vowels , , and , the corresponding independent vowel is added. Thus:  (a), , "okaasan", mother;  (i), にいがた "Niigata", city in northern Japan (usually , in kanji);  (u),  "ryuu" (usu. ), dragon. The mid-vowels  and  may be written with  (e) (rare) ( (), neesan, "elder sister") and  (o) [ (usu ), ookii, big], or with  (i) ( (), "meirei", command/order) and  (u) ( (), ousama, "king") depending on etymological, morphological, and historic grounds.