Yours, Etc.: Origins and Uses of 8 Sign-Offs
1892, from Doktoro Esperanto, whose name means in Esperanto, "one who hopes," pen name used on the title page of a book about the artificial would-be universal language published 1887 by its inventor, Lazarus Ludwig Zamenhof (1859-1917). Cf. Spanish esperanza "hope," from esperar, from Latin sperare (see speed (n.)).