Shu came across the word vum in a poem, which evidently is a regionalism from New England that is used to express surprise, as in, "Well I vum!" or "I'll be vummed!" Have you heard it?

The site above then mentioned another regionalism from the south being swan or swanny to mean "swear." That is used as "Now I swanny..."

I hadn't heard of any of these, have you? Do you have some others?

Never heard either of them.

I've been here in NE for some time and have never heard that term.

I have heard the southern expression as swarn, with more of an "r" than if it was "swan".

It's an alteration of vow according to the OED.

swan is "probably northern English dialect I s' wan lit. ‘I shall warrant’ = I'll be bound; later taken as a mincing substitute for swear v."

Each of these poems has the word vum:

Wonderful One-Hoss Shay
and

Darius Greene and His Flying Machine