Easton's 1897 Bible Dictionary:

Sepharvaim
   taken by Sargon, king of Assyria (2 Kings 17:24; 18:34; 19:13;
   Isa. 37:13). It was a double city, and received the common name
   Sepharvaim, i.e., "the two Sipparas," or "the two booktowns."
   The Sippara on the east bank of the Euphrates is now called
   Abu-Habba; that on the other bank was Accad, the old capital of
   Sargon I., where he established a great library. (See SARGON.) The recent discovery of cuneiform inscriptions at
   Tel el-Amarna in Egypt, consisting of official despatches to
   Pharaoh Amenophis IV. and his predecessor from their agents in
   Palestine, proves that in the century before the Exodus an
   active literary intercourse was carried on between these
   nations, and that the medium of the correspondence was the
   Babylonian language and script. (See KIRJATH-SEPHER.)


Hitchcock's Bible Names Dictionary (late 1800's):

Sepharvaim, the two books; the two scribes