>>192872
i'm into nara/heian japanese linguistics and i don't have that much trouble finding open sourced papers that don't require university login, in fact most them are hosted by j-stage and NII which don't have login walls
however they are obviously in japanese, i don't think there is that much academia on kobun/japonic that isn't in japanese so i don't see how you plan to study proto-japonic when you don't have knowledge of japanese to read academia on it nor other stages of it's development to have something to compare it to... maybe you should try picking up japanese since you'll probably enjoy it