Incipient is the light buffet.
You can't tell incipient from the attitude, as you can stall in a high nose attitude, a turn or relatively flat.
You can't tell from the airspeed. Low airspeed isn't always the sign of a stall as you can fly slowly and not stall, and you can stall at high speeds.
And you most certainly can't rely on the stall warner!
Other people may have different outlooks on what the incipient is!