These two documents are from October 1915 and August 1918. The 1915 letter is by Edison's chief engineer Miller Reese Hutchison. It pertains to a special event in San Francisco during which Edison planned to speak over the transcontinental telephone in response to an address recorded on an Edison Diamond Disc Phonograph in West Orange. The 1918 letter contains Edison's statement that he "was the first person to speak into the first phonograph" and that his first words were lines from the nursery rhyme "Mary Had a Little Lamb."
[X012F4A], Letter from Miller Reese Hutchison to Union Noble Bethell, October 19th, 1915 1915-10-19
[X012F4B], Letter from Thomas Alva Edison to John Joseph Carty, August 14th, 1918 1918-08-14