Well for initial training in S/E aircraft airline training schools will teach callouts with the following airspeeds.1.Airspeed Alive, 2. Vr, 3. V2
Take off safety speed (or V2) applies to all aircraft, in a single engined aircraft its the speed you should be at 50ft after takeoff. Anything less you may not have enough control to lower the nose and land without stalling, and anything more you will have a longer take off distance required because the Take off charts assume you are at this speed at 50ft. Both Vr and V2 vary with weight, and for proffesional airline cadet schools students are expected to fill out a data card prior to each flight. V1 does not apply to single engined aircraft. Below V1 you may reject a Takeoff if you have an engine failure. Above v1 you continue even after an engine failure. In a C152 you reject the takeoff at any speed if your engine fails!