In what Orthagraphy does Modern Estonian orthography have its basis?
Modern Estonian orthography is based on the Newer Orthography created by Eduard Ahrens in the second half of the 19th century based on Finnish orthography.
В какой орфографии основана современная эстонская орфография?
Современная эстонская орфография основана на Новой орфографии, созданной Эдуардом Аренсом во второй половине 19 века на основе финской орфографии.