en_tn/isa/27/12.md

It will come about

This phrase marks an important event that will happen.

Yahweh will thresh

AT: "Yahweh, like a farmer separating the grain from the plant, will separate you." (See: rc://en/ta/man/translate/figs-metaphor)

from flowing stream of the Euphrates River, to the Brook of Egypt

AT: "from the Euphrates River in the east to the Brook of Egypt in the west."

you will be gathered one by one

AT: "Yahweh will gather you one by one" (See: rc://en/ta/man/translate/figs-activepassive)

a great trumpet will be blown

AT: "Yahweh will order someone to blow the great trumpet" or "An angel will blow the great trumpet"

the perishing ones in the land of Assyria will come, and the outcasts in the land of Egypt

AT: "those who are in exile and dying in the land of Assyria and the land of Egypt will come"

holy mountain

See how you translated this in Isaiah 11:8.