Why do English translations interpret the Ivri imperative "SOS" (שׂוֹשׂ) / "Rejoice!" as the English adverb "greatly" in Isaiah 61:10?

Question

In the Ivri (עִבְרִי) / Hebrew (ἑβραιου) text of [Isaiah 61:10] we read Rejoice twice as an imperative then in 1ps future tense :

"SOS" (Rejoice!, שׂוֹשׂ), "ASIYS" (I-will Rejoice, אָשִׂישׂ).

• Note the different tenses for "Rejoice" : https://www.pealim.com/dict/2191-lasus/

Isaiah 61:10 [MT]

"Sos Asiys BaYeHoVaH" (שׂוֹשׂ אָשִׂישׂ בַּֽיהוָ֗ה)

Question: Why do English translations interpret the Ivri imperative "SOS" (שׂוֹשׂ) / "Rejoice!" as the English adverb "greatly" in Isaiah 61:10?

Isaiah 61:10 [KJV] : " I will greatly rejoice in the Lord "

Isaiah 61:10 [NASB] : " I will rejoice greatly in the Lord "

Isaiah 61:10 [ESV] : " I will greatly rejoice in the Lord "

English translations change "Rejoice!" into an adverb "greatly". Yet the Ivri (עִבְרִי) word for "greatly" = "Gedool" (גְדֻלָּ), "great" = "Gadol" (גָּ֘ד֥וֹל). The verb "Asiys" (אָשִׂישׂ) does not contain the "gedul" (greatly) adverb.

Is there any reason why English translations interpret "SOS" (שׂוֹשׂ) as "greatly"?

Answer 1

In Hebrew, a word is repeated for emphasis. It is a common technique. In this case, there is a repetition of a word with a change in the form of the word.

The first example is in Genesis 2:17, New International Version:

but you must not eat from the tree of the knowledge of good and evil, for when you eat from it you will certainly die."

you will surely
מ֥וֹת (mō·wṯ)
Verb - Qal - Infinitive absolute
Strong's Hebrew 4191: To die, to kill

die
תָּמֽוּת׃ (tā·mūṯ)
Verb - Qal - Imperfect - second person masculine singular
Strong's Hebrew 4191: To die, to kill

Other examples follows:

Deuteronomy 10:17 (NASB) “For the LORD [Yahweh] your God is the God of gods and the Lord of lords, the great, the mighty, and the awesome God who does not show partiality nor take a bribe.

Song of Solomon 1:1 This is Solomon’s Song of Songs.

Ecclesiastes 1:2 Vanity of vanities, says the Preacher, vanity of vanities! All is vanity.

1 Samuel 3:10 The LORD came and stood there, calling as at the other times, "Samuel! Samuel!" Then Samuel said, "Speak, for your servant is listening."

Ezekiel 26:7 For thus says the Lord GOD, “Behold, I will bring upon Tyre from the north Nebuchadnezzar king of Babylon, king of kings, with horses, chariots, cavalry and a great army.

John 6:4 Truly, truly, I say to you, he who believes has eternal life.

And many more ...