Conversation so far:
When did Alexander Graham Bell begin his early work on the telephone?
Returning to Boston in fall 1873, Alexander Graham Bell made a fateful decision to concentrate on his experiments in sound.
What led to Alexander Graham Bell's discovery of the telephone?
Alexander Graham Bell had long been fascinated by the idea of transmitting speech, and by 1875 had come up with a simple receiver that could turn electricity into sound.
What was happening at the time of Alexander Graham Bell's discovery?
In 1874, at the time of Alexander Graham Bell's discovery, telegraph message traffic was rapidly expanding and in the words of William Orton, had become the nervous system of commerce.

Question: What can you tell me about his discovery of the telephone?
Self-contained rewrite: What can you tell me about Alexander Graham Bell's discovery of the telephone?