In the "Техника – молодежи" magazine, №5 1977, there is a sci-fi story translated from English, "A Task for Emmy", it is about a super-computer called "Эмми". The story has a phrase that puzzled me, "тысячи милей ее проводов". All my dictionaries (Dahl, Ushakov, Ozhegov, Zaliznyak) say "миля" is the 1st declension soft variant, that is the genitive case plural should be "миль", like "пуля – пуль". What is that "милей" form? Can that be an archaic/regional variant? Or is it just a mere typo or the translator's mistake? I have been reading "Техника – молодежи" for all my life and so far I have never seen even a single typo in it.
Well, it feels almost like cheating but once again Google Ngram Viewer turns out to be a nice research tool at least for getting started:
So, it's actually pretty clear that
милей never was as popular as
миль. Which is actually kinda strange, since there's no obvious reason for this. In wiktionary it is mentioned, that in Zaliznyak's classification
миля belongs to type 2a - that means "слова с основой на мягкий согласный, ударение всегда на основу" - but, say
олень or even pretty rare
киль do not follow that pattern.