Depends on the various sounds and what kind of keyboard he/she is playing them on.
First, , thanks for you reply. It was well thought out for sure! I hope you don't mind me asking, as I am not challenging your opinion so much as trying to understand.
1-So the type of sound is what determines if it is an instrument, not if it is "pitched" to, as an example, key? Am I understanding that correctly?
2-The input device would determine if the person is a musician or not? Not if the person is using music theory, or creating music? More specifically, a piano controller would make the person a musician, however using a keypad controller (even if mapped as a piano) would negate the person as a musician?
As far as meanings of words, it is a natural part of language to have words meanings change or even evolve. Gay, rubbers, sick, bad...all examples.
Just because it is the general consensus doesn't mean it isn't already changing. The fact that we have people in this discussion with opposing views shows there is a shift. We are not all here agreeing on the meaning.
Technology is one of those things that really pushes change in wording. I don't care how many people in 1995 would all agree that they know exactly what a phone is. It is not the thing I carry in my pocket today! The meaning of "phone" has changed, as is the definition of musician.
Just my two cents. I get the feeling I'm getting two cents back in change though

Seriously, thanks for you well thought out, and well exampled posts. I truly enjoy them!