Do you ever find that when you want to explain something to someone you just end up speaking incoherantly? I find that if I know and have a picture in my mind of what I'm trying to say it's sometimes difficult for me to get the words in the right order for them to make sense to someone else.
Most recently, this happened at work. I was trying to do a price check for one of the cashiers and was having difficulty locating the item. It was a set of 36 colored pencils. I had found a set of 24, but couldn't find the set of 36 anywhere (normally you'd expect items that are that similar to be right next to eachother.) I passed by the cashier's counter and attempted to quickly explain to her that I hadn't yet found the item, but was still looking for it. What came out was something that made completely no sense, I said something like "it's 24, the smaller set, but it's not there and I'm looking now, be right back," which, obviously, she had no idea what I was referring to, and she just said "What?" and looked at me quite confused. I came back again when I checked the other location I thought it might be in (which it wasn't) and I started once again speaking incoherantly. After a few moments of her staring confusedly I realized I was making no sense, and it felt like my head was going in circles. I had to pause, take a breathe, and say "Ok, hold on, I can't talk." Before I could even begin to start speaking again.