Newsflash: Being Sarcastic Can Backfire
To the interpreter from 23 April:
I'm sorry I don't know your name. I would like to apologize more personally. I'm so sorry that you were hurt by our words and actions. We didn't mean it. Really.
You see, one of my co-workers was being an idiot. He thought you were Hispanic, just because you have black straight hair and tan skin. He was going to flirt with you by learning some Spanish words to flirt with you. Then I told everyone that you were an Arabic interpreter, not a Spanish interpreter. We laughed at the stupid ethnocentrism of my co-worker, at how he made assumptions about you just based on how you looked.
In hindsight, I can imagine how it sounded, just hearing some of the words and hearing us laugh. I can understand why you thought we were making fun of you and Arabic people. And I cannot tell you how sorry I am, even though we were not making fun of you.
When you left, I thanked you for coming. I said: "Thank you. It was really uncomfortable not being able to communicate with [the customer] earlier." I was - and am - grateful at the service you and other interpreters provide for our customers. Without you, we would not be able to take good care of them.
Please - whether you see this online or get the more formal version I wrote - understand that what you thought you heard wasn't what was really going on. And I am so sorry that you were hurt - no matter what anyone's intent was.
And everyone else: Make sure that everyone who can hear you knows that you're being sarcastic.