Christmas letter preparation

I've started to get ready for Christmas. First thing, get the cards and letter out. When discussing this with Four, she didn't get it. I explained to her that we will send a card, picture and letter to our friends and family. "What letter?" she said. I said a letter daddy and I wrote. I explained further. It wasn't until she got frustrated and repeated her question that I got it. She's learning the alphabet and wanted to know what specific letter would be on the paper. Kids. She's getting smart fast.