Dagesh - Dagesh Hazak

Dagesh Hazak or Dagesh Hazaq (דגש חזק, "strong dot" – i.e. gemination dagesh, or דגש כפלן, often referred to as "dagesh forte") may be placed in almost any letter, this indicated a gemination (doubling) of that letter in pronunciation in forms of Hebrew earlier than modern Hebrew. This phonemic variation is not adhered to in Modern Hebrew and is only used by current speakers of Hebrew in situations for careful pronunciation, such as reading of scriptures in a synagogue service, recitations of biblical or traditional texts or on ceremonious occasions, and then only by very precise readers.

The following letters, the gutturals, almost never have a dagesh: aleph א, he ה, chet ח, ayin ע, resh ר. (A few instances of resh with dagesh are Masoretically recorded in the Hebrew Bible, as well as a few cases of aleph with a dagesh, such as in Leviticus 23:17.)

The presence of a dagesh hazak or consonant-doubling in a word may be entirely morphological, or, as is often the case, is a lengthening to compensate for a deleted consonant. A dagesh hazak may be placed in letters for one of the following reasons:

1. The letter follows a definite article. For example, שָׁמָיִם shamayim "heaven(s)" in Gen. 1:8 becomes הַשָּׁמַיִם hashshamayim "the heaven(s)" in Gen 1:1. (Occasionally, the letter following a He used to indicate a question may also receive a dagesh, e.g. Num. 13:20 הַשְּׁמֵנָה הִוא "whether it is fat").
2. The letter follows the prefix mem- with the hirik vowel (i); where this prefix is an abbreviation for the word min, meaning "from". For example, the phrase "from your hand", if spelled as two words, would be מִן יָדֶךָ min yadecha. In Gen. 4:11, however, it occurs as one word: מִיָּדֶךָ miyyadecha.
3. It marks a missing double letter. For example, compare Ex. 6:7 לָקַחְתִּי lakachti with Num. 23:28, where the first letter of the stem has been elided: וַיִּקַּח vayyikkach.
4. If the letter follows a vav consecutive imperfect (sometimes referred to as vav conversive, or vav ha'hipuch), which, in Biblical Hebrew, switches a verb between perfect and imperfect. For example, compare Judges 7:4 יֵלֵךְ yeilech "let him go" with Deu. 31:1 וַיֵּלֶך vayyeilech "he went".
5. If it is a marker of the binyan. For example:
(a) It is placed in the first letter of the root of a word in the imperfect form in the binyan niphal;
(b) It is placed in the second letter of the root of a word in the binyan piel (e.g. Ex. 15:9 אֲחַלֵּק achalleik "I shall divide") or the binyan pual;
(c) It is placed in the second letter of the root of a word in the binyan hithpael, e.g Gen. 47:31 וַיִתְחַזֵּק vayitchazzeik, "he strengthened himself".

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