Proper noun
Old Japanese
the oldest stage of the Japanese language; spoken through the 8th century and followed by Late Old Japanese
A different kind of issue is that of the Old Turkish genitive /Xŋ/ (where "X" stands for any phoneme) and Old Japanese genitive /no/. Source: Internet
Also, the doublet wo meaning "hemp" is attested in Western Old Japanese and Southern Ryūkyū. Source: Internet
The first of them is that Old Japanese for the first person pronoun ("I", in English) was neither /ba/ or /a/. Source: Internet