I'm not exactly sure what you're talking about - NES FF2 Dawn of Souls? I've never heard it called that - I thought it was just FF2 for NES. Maybe you're talking about the difference between the newer translations and the much older ones for FF2 & FF3 on NES?
The way I understand it the new translations used words that were used on newer remake versions of the game like maybe the DS remake versions and the older ones were just the first translation of the game that had nothing to do with the way words were said in the new remake versions. It's for people who prefer the words in the new remake versions or something.