I'll try to remember never to let Robert G instruct me. The FAA will give anyone a "certified" license, so it seems. Shame Robert, you should know how and why Vne is determined.
Back to the question,
The wing shape DOES have some effect on speed. It's the horsepower the engines put out that make a plane fly faster and higher. More power, more speed more lift. But there are limitations.
The basics of aerodynamics. Lift, Weight, Thrust, Drag.
The strength of the airplanes structure is part of what determines it's maximum speed.
The VNE , or the never exceed speed, of an aircraft is the V speed which refers to the velocity that should never be exceeded due to risk of structural failure, due to calculated factors such as wing or tail deformation or due to aeroelastic 'flutter' (unstable airframe or control oscillation). VNE is specified as a red line on many airspeed indicators. This speed is specific to the aircraft model, and represents the edge of its performance envelope in terms of speed. Well below the speed of sound, the VNE is read as Indicated Air Speed (IAS), since the pitot indication is a direct measure of the dynamic pressure for any given airspeed. At altitude, where TAS is higher than IAS, aerodynamic damping is weaker than at lower levels (damping is proportional to IAS) whereas inertia-induced disturbances are stronger (inertia grows with acceleration, which is the time derivative of TAS). This condition, if continued beyond tested limits, pre-disposes to unstable oscillations or 'flutter'. For instance, the TAS/IAS ratio at 40,000 ft on the ICAO ISA is 2:1, that is, TAS is approximately twice IAS.
Visit: http://www.howstuffworks.com/airplane.htm
You'll get a better understanding.