they knew.

Judges 12:6
they told him, "Please say Shibboleth." If he said, "Sibboleth, " because he could not pronounce it correctly, they seized him and killed him at the fords of the Jordan. So at that time 42, 000 Ephraimites were killed.

Genesis 27:22
So Jacob came close to his father Isaac, who touched him and said, "The voice is the voice of Jacob, but the hands are the hands of Esau."

Matthew 26:73
After a little while, those standing nearby came up to Peter. "Surely you are one of them, " they said, "for your accent gives you away."

and what hast

Isaiah 22:16
What are you doing here, and who authorized you to carve out a tomb for yourself here, to chisel your tomb in the height and cut your resting place in the rock?