ethnicity is a matter of self identification language is only relevant to the extent that it influences people's self identification if people don't feel they're ethnically iranian but only persian or kurdish or ossete or whatever so that we have to rely on language then there's really no such thing as iranian people and this article should be redirected to iranian languages if iranian is a real thing then language isn't critical so do persians parsis tajiks kurds and ossetes think of themselves as being one people or part of a coherent group of peoples if so then iranian is a real thing if not it's an invention of linguists or historians