pretenso

In school orchestra I had a conductor who consistently called the cellos the "celli."   At one point he referred to some composer's "celli concerti," which gave it all away.  Right?  Those were pieces for solo cello and orchestra, not for groups of cellists playing with an orchestra.   So if he's gonna be all Mr Correcto he would have said "cello concerti."

Or he could realize that those are English words now, and use an s.

(Did he say violino and violini?  No, he did not.)