Zajednički predak svih jezika u ovoj porodici zove se praindoiranski, također poznat kao zajednički arijski, koji se govorio otprilike krajem 3. milenijuma pre nove ere u zapadnoj Rusiji. Tri grane modernih indoiranskih jezika su indoarijski, iranski i nuristanski. Četvrta nezavisna grana, dardska, ranije je bila postavljena, ali nedavna istraživanja općenito stavljaju dardske jezike kao arhaične članove indoarijske grane.[4]
Ova grana je također poznata kao arijski jezici, što se odnosi na jezike kojima govore arijski narodi, gdje je pojam arijski etnokulturna samooznaka starih Indoiranaca. Ali u modernom dobu, zapadni naučnici izbjegavaju izraz Arijci od Drugog svjetskog rata, zbog percipirane negativne konotacije povezane s arijanizmom.
^Jadranka Gvozdanović (1999). Numeral Types and Changes Worldwide. Walter de Gruyter. str. 221. ISBN978-3-11-016113-7.: "The usage of 'Aryan languages' is not to be equated with Indo-Aryan languages, rather Indo-Iranic languages of which Indo-Aryan is a subgrouping."
^Bashir, Elena (2007). Jain, Danesh; Cardona, George (ured.). The Indo-Aryan languages. Routledge. str. 905. ISBN978-0415772945. 'Dardic' is a geographic cover term for those Northwest Indo-Aryan languages which [..] developed new characteristics different from the IA languages of the Indo-Gangetic plain. Although the Dardic and Nuristani (previously 'Kafiri') languages were formerly grouped together, Morgenstierne (1965) has established that the Dardic languages are Indo-Aryan, and that the Nuristani languages constitute a separate subgroup of Indo-Iranian.
Kümmel, Martin Joachim. "The morphology of Indo-Iranian". In: Handbook of Comparative and Historical Indo-European Linguistics. Volume 3. Edited by Jared Klein, Brian Joseph and Matthias Fritz. Berlin, Boston: De Gruyter Mouton, 2018. pp. 1888–1924. https://doi.org/10.1515/9783110542431-032
Kümmel, Martin Joachim. "Indo-Iranian". In: The Indo-European Language Family: A Phylogenetic Perspective. Edited by Thomas Olander. Cambridge: Cambridge University Press, 2022. pp. 246–68. doi:10.1017/9781108758666.014.
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Pinault, Georges-Jean. "Contacts religieux et culturels des Indo-Iraniens avec la civilisation de l'Oxus". In: Comptes rendus des séances de l'Académie des Inscriptions et Belles-Lettres, 149e année, N. 1, 2005. pp. 213–257. DOI:https://doi.org/10.3406/crai.2005.22848 ; www.persee.fr/doc/crai_0065-0536_2005_num_149_1_22848
Pinault, Georges-Jean. "La langue des Scythes et le nom des Arimaspes". In: Comptes rendus des séances de l'Académie des Inscriptions et Belles-Lettres, 152e année, N. 1, 2008. pp. 105–138. DOI:https://doi.org/10.3406/crai.2008.92104 ; www.persee.fr/doc/crai_0065-0536_2008_num_152_1_92104
Nicholas Sims-Williams, ured. (2002). Indo-Iranian Languages and Peoples. Oxford University Press.