>>>>sagovornik - go-between
>>>
>>>Nope, that's the "potrcko" (the runabout, literally) or "posrednik" (middleman). Sagovornik is interlocutor in English - but nobody uses that word; I haven't heard it ever, just found it when I was checking. Sa=with, govoriti=speak, so, co-speaker, partner in conversation. Two people who talk are sagovornik to each other.
>>
>>Go-between is also an interlocutor. How about "Arbiter"?` (the interlocutor in a dispute)
>
>The person you're talking with, . Just talking, literally, with-speaker (yep, govornik means speaker, orator).

Well I don't know. An interlocutor, to me, is someone who speaks to both parties, on their behalf(s). From the latin "to speak between" afaik.