Hebrew alphabet written from right to left. It has 22 letters, five of which use different forms at the end of a word. In the traditional form, vowels are indicated by the weak consonants Aleph (), He (), Vav (), or Yodh () serving as vowel letters, or "matres lectionis": the letter is combined with a previous vowel and becomes silent, or by imitation of such cases in the spelling of other forms. Also, a system of vowel points to indicate vowels (diacritics), called niqqud, was developed. In modern forms of the alphabet, as in the case of Yiddish and to some
Hebrew alphabet was an abjad consisting only of consonants, but is now considered an "impure abjad". As with other abjads, such as the Arabic alphabet, during its centuries-long use scribes devised means of indicating vowel sounds by separate vowel points, known in Hebrew as "niqqud." In both biblical and rabbinic Hebrew, the letters can also function as "matres lectionis", which is when certain consonants are used to indicate vowels. There is a trend in Modern Hebrew towards the use of "matres lectionis" to indicate vowels that have traditionally gone unwritten, a practice known as "full spelling". The Yiddish alphabet, a modified version