Mater Lectionis
The usage of certain consonants to indicate a vowel in the spelling of Hebrew, Aramaic, and Syriac languages is called matres lectionis (Latin "mothers of reading", singular form: mater lectionis, Hebrew: אֵם קְרִיאָה mother of reading). The letters that do this in Hebrew are א (aleph), ה (he), ו (waw) and י (yod). The י…