"One grają na skrzypcach."

Translation: They play the violin.

[AnCatDubh]

Why not ‘on the violins’?

[Jellei]

I'm pretty sure that in English you play the instrument, and not on it.

[knoakes]

this means they are actually playing rather than have the ability to play?
So although subtle there is a difference between "they are playing a violin" which is less specific than "they play the (specific) violin" do I assume without articles you would use "this " or "that" or do you Use different verbs to describe more specific playing?

[va-diim]

They can't play "a violin" because they are more than one person. "They're playing violins." Or, "They play the violin," meaning that they are violin players.