See data and maps.
Moroz, G. (2021). “Long vowels”. In: Typological Atlas of the Languages of Daghestan (TALD). Ed. by M. Daniel, K. Filatov, T. Maisak, G. Moroz, T. Mukhin, C. Naccarato and S. Verhees. Moscow: Linguistic Convergence Laboratory, NRU HSE. DOI: 10.5281/zenodo.6807070. http://lingconlab.ru/dagatlas.
@incollection{moroz2021,
title = {Long vowels},
author = {George Moroz},
year = {2021},
editor = {Michael Daniel and Konstantin Filatov and Timur Maisak and George Moroz and Timofey Mukhin and Chiara Naccarato and Samira Verhees},
publisher = {Linguistic Convergence Laboratory, NRU HSE},
address = {Moscow},
booktitle = {Typological Atlas of the Languages of Daghestan (TALD)},
url = {http://lingconlab.ru/dagatlas},
doi = {10.5281/zenodo.6807070},
}General chapter: Phonology
Long vowels are present in northern Dagestan, Chechnya and Ingushetia. They are not present in Avar and southern Dagestan. However, there are a few cases where they are reported as the result of some intervocalic consonant deletions.