thanks for the detailed explanations concerning Ranha.
>As for your second question, the evaluation of Datia > Daik, etc. will only
be possible if you are more specific about the source form, the historical
background, >and the languages that show the forms in question. As I said at
the beginning, a lot depends on language-specific patterns.
The modern name of the Ural river appeared only in 1775, after the Pugatchov
rebellion. The previous name of the river was Yaik, and Russian speaking
people who lived there and very actively supported Pugatchov were Yaik
Cossacks. To "forget" their name the river was renamed.
The name Yaik came into Russian from Turkic languages - Jejek (or Yeyek in
other transliteration) in Chuvash, Zhajyk in Kazakh.
However this term was mentioned much earlier by Ptolemey in the form of Daix
(not Daik, as I erroneously wrote before!) and by Menander Proteus in the
form of Daich, with the last (4th) letter "ksi" and "chi" respectively. So I
believe this name must be of the East Iranian origin. Could it theoretically
descend from Avestan Datia?