grateful to be a native speaker of English

[lauradi7dw]

I was watching videos of the empty can/full can test for supraspinatus problems (no actual cans are involved. They are imaginary cans). I thought this one was good, but it seems to me that empty and can are regular words, not jargon terms - why do they still use the English words? This wasn't the only example. I guess for people who don't know any English, it's just like the tests that are named for the folks who invented them (or first described them in the literature).
http://www.youtube.com/watch?v=a7itYGBCwWo