Duotang is a brand name only; I have never heard anyone call a folder a duotang. Maybe a duotang folder, but rarely, in my experience. We just call them folders; maybe a pocket folder, if they have them (pockets, that is). I just looked at an on-line office supply site. They list them as "Combination Folders with Fasteners", and have Duo-tang listed as the manufacturer.

As to deskew--do you know how it's pronounced? I suspect it's something like duh-SKEW; however, I find myself thinking DESK-you, which sounds gratifyingly insulting! This was a new word to me, too; my photo suite just says flip/rotate; in Paint, I have the option to skew.

I came across my sellotape yesterday, as it happens; gave me an ear-to-ear smile, as I remembered purchasing it!