I hope that you are able to speak with them next time... and that they are discouraged from darkening your doorstep in the future.
It kinda reminds me of one time when I was a JW... there was this older anglo JW, Fred, and a younger Hispanic JW, Rudy, going door-to-door. The city that I live in has many Hispanics here, and the older gentleman knocked on a door, and a Hispanic fella answered it. He gave Fred a "I don't speak Eenglish." type of response, and Fred said something like, "Oh!" and then calls out to Rudy out at the sidewalk, on his way to the next door.
"Rudy", he sez, "come here and talk to this gentleman. He doesn't understand English."
Well, Rudy came up, and started talking Spanish to the fella at the door. Rudy knew Spanish very well, having been raised in a household where both his mother and father were from Mexico. He started his presentation in Spanish - speaking at 90-miles an hour.
The fella at the door said, "Whoa! Stop! I don't understand Spanish! I just told you that to try to get rid of you!"
It was funny.