how are Finnish and Japanese fairly similar? i'm curious what you see that would make them so.
"There is general agreement on several typological similarities being widely found among the languages considered under Ural–Altaic:
head-final and subject–object–verb word order
in most of the languages, vowel harmony
morphology that is predominantly agglutinative and suffixing zero copula
non-finite clauses
lack of grammatical gender
lack of consonant clusters in word-initial position
having a separate verb for existential clause which is different from ordinary possession verbs like "to have""
It's actually even more complicated than that: yabanjin is a kan'on/Tang dynasty era borrowing, so it came from the Middle Chinese spoken in Chang'an/Xi'an around the 8th century, which would have been quite different from the modern Mandarin yemanren.