Hebrew orthography includes three types of diacritics: * Niqqud in Hebrew is the way to indicate vowels, which are omitted in modern orthography, using a set of ancillary glyphs. Since the vowels can be understood from surrounding, context can help readers read the correct pronunciations of several letters of the Hebrew alphabet (the rafe sign and other rare glyphs are also listed as part of the niqqud system but are not in common use); * geresh and gershayim, two diacritics that are not considered a part of niqqud, each of which has several functions (e.g. to denote Hebrew numerals); * and cantillation, "accents" which are used exclusively to indicate how Biblical passages should be chanted and may possess a punctuating function.