Quote Originally Posted by Galician View Post
Is it related in any way to the dual voice in ancient Greek?
I would bet that it does. I don't think dual lasted very long in English, as we got rid of a lot of a lot of morphology inherited from Proto-Germanic and ultimately from Proto-Indo-European (PIE). Since Greek is a PIE language (yummm!), I wouldn't be surprised if PIE had a dual form that some of its daughter languages inherited.

Of course, as a linguist I try to never give a straight answer, so it could be that these two uses of a dual form arose independently in both languages.