matres lectionis

Matres lectionis (Latin "mothers of reading", singular form: mater lectionis) is an early method for indicating vowels in the Hebrew alphabet. The consonant letters Yod י,  Waw ו and  ’Aleph א were used to give a rough indication of the quality of long vowels. Most commonly, Yod י indicates i or e, while Waw ו indicates o or u. ’Aleph א was not systematically developed as a mater lectionis in Hebrew (as it was in  Aramaic and Arabic), but it is occasionally used to indicate an a vowel. (However, a silent ’Aleph — indicating an original  glottal stop consonant sound which has become silent in Hebrew pronunciation — can occur after almost any vowel.) At the end of a word, He ה can also be used to indicate that a vowel should be pronounced. In some verb forms, matres lectionis are used almost always. Examples: Later, it became clear that the system of matres lectionis did not suffice to indicate the vowels precisely enough, so that supplemental vowel pointing systems (diacritic symbols indicating vowel pronunciation and other important phonological features not written by the traditional basic consonantal orthography) were developed accordingly.
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