Welcome, Ib5989!
Let's see.... WiFi is a technology for connecting computers in a local network that works with radio waves, and is different from the cell phone signal...
BlueTooth is a radio application to connect headphones and such to a computer...
A2DP is a BlueTooth "subprogram" that allows you to use stereo headphones/headsets and answer phone calls while you are at it...
MDA is a MultipleDesignationApparatus, since it is being sold under a number of names worldwide, with very small design changes between each other... such as the 8125...
God luck, and let us know how it goes!