This song troubles me and I feel the lyrics may be wrong, certainly wikipedia has both the lyrics and the translation wrong. I always felt that the hero implies that he’s going to hell because he’s mentioning the fire and not on the mountain which is not too far away from his love he wants to escape and forget
Sagliere means raise but it means also climb with no direction I think
'ncoppa means on and on top of but certainly not up or high and surely the song would be much clearer if the refrain mentioned a direction like “jamme ‘ncielo” which wouldn’t change the metre. Jamme means either let's go, or come on, or let me go and has other interpretations too depending on the context so I took the middle path saying just going, I think the exact meaning here is let me leave.
What I don’t know is if the second verse starts “Nèh, jamme da la terra a la montagna” meaning “Well, I’m going from the earth to the mountain” or “Nè jamme da la terra a la montagna” which is “Nor am I going from the earth to the mountain” and this is the reason that earth is mentioned because he’s leaving earth possibly either embarking (climbing sails) to Africa or enlisting or even killing himself (climbing to hell).
Now that I've read the song in depth I feel that the most probable explanation is embarking and thus the title of the song funiculì, funiculà which almost certainly relates to ropes and the words might were also actual on ship terms or orders for the neapolitan navy, something like heave in and heave away. So here 'ncoppa means just aboard, which makes more sense to me since neapolitans are sea pople and it's hard to imagine someone escaping to a mountain and not to the sea.
I've read also italian translations that all imply he's climbing a mountain, so here funiculì funiculà may just playfully mean ffune cu lì ffune cu là (string over here, string over there) referring to the strings that split his mind going back and forth to his darling
I also think that the original lyrics are intentionally ambiguous since the hero maybe hiding his destination from his darling.
So if you have accurate information about this great classic please drop a line