A better explanation (Maybe.)
I've written that the telephone is an electrical instrument. Electricity powers the phone and it carries or conveys your voice from the telephone to the local switch. Not exactly. Electricity on two wires flows or is conveyed to work the phone itself: to operate the keypad, to make it ring. But electricity does not carry the voice.
Electric current doesn't convey the voice, sound simply varies that current. It's these electrical variations, analogs of the acoustic pressure originally spoken into the microphone, that represent voice. We have two different points here: about the current itself, and, about how that current is altered.
To sum up, electricity is indeed conveyed to the phone, whereupon 1) the current operates the telephone and 2) the current is varied by the voice to communicate. The diagram linked below makes this far more simple than a word description.
The telephone is an electrical instrument. Speaking into the handset's transmitter or microphone makes its diaphragm vibrate. This varies the electric current, causing the receiver's diaphragm to vibrate. This duplicates the original sound. Take a look at this image to make this point much clear.
