What is Alexander graham bells hypothesis when he was building the telephone?

Alexander Graham Bell's hypothesis when building the telephone was that sound could be transmitted over wires as electrical signals. He believed that by converting vocal vibrations into electrical impulses, these impulses could then be sent through a conductor and translated back into sound at the other end. His experiments focused on the idea that speech could be replicated electronically, ultimately leading to the invention of the first practical telephone. Bell's work combined principles of acoustics and electricity, aiming to improve long-distance communication.