Strange short term memory problem - cause/treatment?

Here's an odd one: I just discovered that I have an odd mental deficiency. When I am typing (or writing), and someone is spelling a word I don't know, I find they have to go very, very slow to order for me to follow along. The recent example that tipped me off to this was working with someone, and typing in some names of people that I didn't know how to spell. He had to repeat the spelling of the name 4 or 5 times for me to get it, ultimately going down to just one-letter-at-a-time-nice-and-slow.

From my point of view, it is almost like I can only hold the last letter in my head at any one time. Now, I have no trouble processing information in word I know - I can touch type as fast as someone can speak.

Same is true for someone giving me a phone number I don't know and trying to dial it at the same time. I can do it, but clearly not at a 1/4 of the speed of most other people.

Finally, if I'm, say, working with two documents and I have to copy 4 pieces of data from one to the other, I seem to have a lot of trouble remembering the data as soon as I change to the other document. So if two numbers are, say, 122 and 421, I might have to flip back and forth a few times to get the numbers as they seem to just "disappear" from my brain as soon as I flip to the second document.

Now, I've just recognized that this has always been the case - I've always had this issue, but this is the first time I've really noticed that it is just something my brain seems unable to do.

The question at the end of this long post: is there a name for this syndrome? I doubt there's anything to be done about it, but I'm just curious if this is a recognized condition.