I couldn't agree more with you Jonathan about the beauty that lies in some of these words. I'm sure you and I both and all other baristas alike go into a cafe that we do not work at and order drinks in the same way they were ordered many years before us. Lets also remember however that it's 2009! Hipsters multiply in a way that breaks all laws of modern science. My thoughts are that if they want to call it a "cap" or "spro" (the ladder I'm guilty of using on many occasions) then so be it. As long as they respect its roots and heritage and hopefully grow out of the slang at some point.
I don't know if the words were changed in attempts to make them hip or cool. I would be willing to say out of convenience. Back in 2003 at my first roastery my business partner and I would write "spro" on the bags of espresso going to our cafe so we wouldn't have to waste labels used for wholesale on our cafe we did similarly when I went on to work at the Ugly Mug and I know others at the time were throwing it around as well. We didn't use it while serving customers. Also if there was a small chance that we were both working at the cafe we never wrote down orders we had a system for hollering drinks at each other, it was part of the show that our customers loved anyways just as a good server never writes a whole order we never called the full name one of the things we used was cap. It was never intended to bastardize the name. Of course I know the origin of the words and that cappuccino means little hood named after the capuchin monks. I don't know if it was ever meant to be a hip or cool thing. Also ordering espresso isn't authentic to the Italian ordering process. I would say the allotment of different sized cappuccini has done more to bastardize it than calling it cap.
Yes we are that lazy, we call french fries or pommes frites-fries, bicycles-bikes, caffe latte-latte, caffe or caffe espresso-espresso the list goes on. If you order just a latte in Italy you get milk. We don't actually use any of the proper names anyways so were not really bastardizing them by making them faster in a work environment.
Look to Starbucks if you wish an accurate example of the bastardization of a word. The examples you've given are simply abbreviated forms of the original word and are still semantically correct. There is no ambiguity when I hear or say 'Spro', 'Cap', or whatever. How you've drawn a connection between a lack of appreciation for coffee culture and history with the proliferation of new slang within the industry is... not apparent to me at all. Kind of sounds like you're being a fuddy-duddy (slang circa 1904). ;)