The word used for change
(הפך) is common in the Old Testament and can have any number of senses depending upon the context. For example, it can mean to overthrow (Jonah 3:4; Haggai 2:22), to spin around (Genesis 3:24), to change (Jeremiah 31:13) or turn into something else (Exodus 7:20), to change one’s mind (Exodus 14:5), to turn away (1 Samuel 25:12), or to turn against someone (Job 19:19).
When the Lord is the subject, the verb is used to describe his mighty work; for example, the destruction of Sodom and Gomorrah (Genesis 19:21, Genesis 19:25, Genesis 19:29; Deuteronomy 29:23; Jeremiah 20:16; Amos 4:11), the turning of the Nile into blood (Exodus 7:17), the changing of Balaam’s curses into blessing (Deuteronomy 23:5), and the Lord’s power over creation (Job 9:5; Job 12:15) and over the rulers of the earth (Job 34:25). The verb can also describe the Lord’s work of redemption for his people (Psalm 30:12; Psalm 41:4), especially in relation to the exodus (Psalm 66:6; Psalm 78:44; Psalm 105:25, Psalm 105:29; Psalm 114:8).
Thus, context is the primary determining factor for understanding the nuance of the term. Here in Zephaniah 3:9–13 there is a clear emphasis on a redemptive change
or turning.
The usage of the term here is unique, however, as there is no other example where it expresses to bring x back to y.
The prophet must have chosen the verb because of its overtones of wrath: when more and more anger is to be expected, suddenly hope is shining, for light has dawned.
1 The Lord is about to do something momentous.2
9 “For at that time I will change the speech of the peoples to a pure speech, that all of them may call upon the name of the LORD and serve him with one accord.