Arcaicam Esperantom or Arqhaicam Esperantom, is a constructed auxiliary sociolect for translating literature into Esperanto created to act as a fictional 'Old Esperanto', in the vein of languages such
Proto-Esperanto is the modern term for any of the stages in the evolution of L. L. Zamenhof's language project, prior to the publication of Unua Libro in 1887.