Genesis 42:23 KJV
And they knew not that Joseph understood them; for he spake unto them by an interpreter.
Genesis 42:23, King James Version
In context
22 And Reuben answered them, saying, Spake I not unto you, saying, Do not sin against the child; and ye would not hear? therefore, behold, also his blood is required.
23 And they knew not that Joseph understood them; for he spake unto them by an interpreter.
24 And he turned himself about from them, and wept; and returned to them again, and communed with them, and took from them Simeon, and bound him before their eyes.