LERX: leading edge wing root extension. Those extra triangular bits at the front of the wing, beneath the cockpit and above the engine inlets. They increase the lift of the wing. High alpha: high angle of attack. Angle of attack (AoA, roughly defined): angle between the direction the wing is moving and the airflow incident on it (imagine a wing flying through the air with its bottom facing the flow, that's an AoA of 90 degrees). All wings stall (lose lift) above a critical AoA, as flow separates from the top part of the wing. Vorticity: check below¹. Vortices (very generally) are "shed" along any sharp edges, including LERXes. Through magic, vortices can contribute to lift and entrap/constrain flow, so deliberate creation of vortices and managing where they go is part of designing high performance aircraft and racecars.

^(¹Vortices are spinning/circulating bits of flow, where the spinning dominates over movement in a straight line. It can be visualized by looking at the isosurfaces [surfaces where the values of a parameter are equal] of a parameter called the q-criterion, which is the second derivative of the velocity gradient tensor if I remember correctly. Further explanation needs knowledge of fluid mechanics and differential calculus, usually not appropriate for 7 year olds)