I like to call strikes. I think most of us do. A good catcher "frames" the borderline pitch by turning the pocket of her mitt toward the strike zone. That makes the pitch look maybe a hair better than it was -- and if I do think it was a strike, that helps me. A bad catcher thinks framing a pitch means moving the glove into the zone. As others have said, this just tells me that she didn't think it was a strike either.
Regarding timing, I think you'll find the better plate umpires have a nice consistent delay from the time the pitch hits the glove until they give their verbal call. That gives us time to make the decision on a borderline pitch without an obvious change in rhythm. If your timing changes, you will hear it from whichever side didn't get the call. My first mentor would tap his thigh twice before making the call.
SNAP! ... tap ... tap ... STRIKE! (except he pronounced it "HAAWW!")
