People have played with using magnets in the ear and a coil driver necklace as earphones, and I’ve always wondered if a magnet near your throat would work similarly in reverse, but I’ve never seen anyone actually try it yet
There’s no easily implantable solution for this though, there’s no pre-built microphone or switch implant, so you’ll definitely have to tinker
Or maybe just an external throat-mic is an option? They’re popular for use with radios