Here I am. This is my first nodeshell rescue. This phrase originally started in the african-american community. Sister is a commonly used term to describe a female member of the african-american community and "Amen" usually closes a prayer of the christian faith. This phrase has since evolved into an affirmative statement similiar to "I hear ya'" or "hell yes!" It has since become universal, many people of various descent use it.

It's quite common in the Hebrew Psalms, and when the book was translated to Greek and from Greek to Latin and from there to the other European languages, they just didn't bother to translate it and used a transcript.

Various other words were treated the same.