In the spelling of Arabic and some other Semitic languages, matres lectionis (; from Latin "mothers of reading", singular form: mater lectionis, Hebrew: אֵם קְרִיאָה 'em k'ri'á), refers to the use of certain consonants to indicate a vowel. In Arabic, the matres lectionis (though they are much less often referred to thus) are alif ا, waw و, and ya' ي. The letters that do this in Hebrew are aleph, he, waw (or vav) and yod (or yud). The yod and waw in particular are more often vowels than they are consonants.