Proto-Japanese: *si
Meaning: thou (2d p. pron.)
Russian meaning: ты
Old Japanese: si
Comments: OJ si is not frequent and is sometimes hard to distinguish from the deictic / emphatic particle si; however, there are several text examples firmly identifying its function as a 2d p. pronoun. It is used parallelly with the far more frequent na, but never occurs in compounds or with suffixes -re or -no; it is thus probable that it originally functioned as the direct stem as opposed to na as the oblique stem in a suppletive paradigm. See more detailed discussion in Murayama 1950, Miller JOAL and Itabashi 1998 (pace the latter author, however, we must say that the coincidence of si 'thou' and si `deictic / emphatic pronoun and particle' must be just a coincidence).
