Gen.42.23

And they knew not that Joseph understood them; for he spake unto them by an interpreter.

Gen.42.23

Joseph had been using an interpreter, so they didn't know that Joseph was understanding every word.

Gen.42.23

They did not realize that Joseph could understand them, since he was using an interpreter.

Gen.42.23

But they did not know that Joseph understood them, for he spoke to them through an interpreter.