In Star Trek 4 'The Voyage Home', in probably the funniest scene in the movie, Scotty tries using a 1980s computer. After a bit of trouble (see below), he realizes he needs to use the keyboard and manages to type out a formula exceptionally quickly (again, see below). My question is, considering his unfamiliarity with that sort of computer, and the fact that (as far as I can recall) there aren't any 'keyboards', or at least QWERTY keyboards, in the 23rd century, where did Scotty learn to type so fast?
The far bigger question to me always has been the question how Scotty knows how to write the formula into the computer. I.e. if you're able to write and format a letter with Microsoft Word, you might still not know how to do all the proper steps in a program such as LibreOffice Writer (without trial and error). And we're not just talking about some UI differences here.
But besides that, once Scotty knew he'd be forced to use the keyboard, he could just use that. Don't forget that it's not like keys or buttons are obsolete in Star Trek, and especially during TOS there are still tons of panels with buttons and keyboard like attachments (even LCARS just mimics panels and stuff, but doing it in a far more dynamic way). Actually, I'm rather sure there are at least a few instances of keyboard like panels in some of the episodes, I jut don't remember any specific one. But remembering the annoying computer sounds in TOS, I could understand them trying not to use them. :)
Don't forget that he's still an engineering genius, so it shouldn't take long for him to figure out that buttons with letters on them are meant to be used for typing. They probably have similar things in the future, especially during TOS. Just don't expect any classic IBM/PC compatible keyboard sitting around. Him using the mouse as some kind of microphone clearly has been a gag for the audience, but at the same time it shows that he knows that older hardware might have been wired and that he'd have to use some of the devices attached through cables.
Oh, and if you'd like a different real life example: Take some kid of today who grew up with touch screen devices and modern PC keyboards only. Put them in front of a 18xx typewriter and let them figure out how to write a letter. There might be a few starting issues (feeding the paper... "Hello, Computer!"), but once those hurdles are taken, actually using the "device" is pretty straight forward, even if you haven't used such "ancient" technology before.
One last note: If you're set to complete a job estimated to take 5 hours within 5 minutes you'll have to have quick fingers, no matter what. Slow fingers won't impress your captain!