The dagesh () is a diacritic used in the Hebrew alphabet. It was added to the Hebrew orthography at the same time as the Masoretic system of niqqud (vowel points). It takes the form of a dot placed inside a Hebrew letter and has the effect of modifying the sound in one of two ways.
An identical mark, called mappiq, has a different phonetic function, and can be applied to different consonants; the same mark is also employed in the vowel shuruk.
Dagesh and mappiq symbols are often omitted in writing. For instance, is often written as . The use or omission of such marks is usually consistent throughout any given context. The two functions of dagesh are distinguished as either kal (light) or ḥazak (strong).
A or (, or , also " lene", "weak/light dagesh", opposed to "strong dot") may be placed inside the consonants bet, gimel, dalet, kaf, pe and tav. They each had two sounds, the original "hard" plosive sound (which originally contained no dagesh pointing as it was the only pronunciation), and a "soft" fricative version produced as such for speech efficiency because of the position in which the mouth is left immediately after a vowel has been produced.
Prior to the Babylonian captivity, the soft sounds of these letters did not exist in Hebrew, but they were later differentiated in Hebrew writing as a result of the Aramaic-influenced pronunciation of Hebrew after this point in Jewish history. The Aramaic languages, including Jewish versions of Aramaic, have these same allophonic pronunciations of the same letters.
The letters take on their hard sounds when they have no vowel sound before them, and take their soft sounds when a vowel immediately precedes them. In Biblical-era Hebrew this was the case within a word and also across word boundaries, though in Modern Hebrew no longer across word boundaries since in Modern Hebrew the soft and hard sounds are no longer allophones of each other, but regarded as distinct phonemes.
When vowel diacritics are used, the hard sounds are indicated by a central dot called dagesh, while the soft sounds lack a dagesh.