WASHINGTON — Researchers have identified the voice of Alexander Graham Bell for the first time in some of the earliest audio recordings held at the Smithsonian Institution.

The National Museum of American History announced Wednesday that Bell’s voice was identified with help from technicians at the Library of Congress and the Lawrence Berkeley National Laboratory in California. The museum holds some of the earliest audio recordings ever made.

Researchers found a transcript of one recording signed by Bell. It was matched to a wax disc recording from April 15, 1885.

“Hear my voice, Alexander Graham Bell,” the inventor said.

The experimental recording also includes a series of numbers. The transcript notes the record was made at Bell’s Volta Laboratory in Washington. Other recordings from the time include lines from Shakespeare....