'Not right away,' says I. - Why the third person singular?

Question

I hope this confuses, and scares the hell out of, well, everybody. Here's a quote from an O.Henry story:

Every few minutes he would remember that he was a pesky redskin, and pick up his stick rifle and tiptoe to the mouth of the cave to rubber for the scouts of the hated paleface. Now and then he would let out a warwhoop that made Old Hank the Trapper, shiver. That boy had Bill terrorized from the start.

'Red Chief,' says I to the kid, 'would you like to go home?'

'Aw, what for?' says he. 'I don't have any fun at home. I hate to go to school. I like to camp out. You won't take me back home again, Snake-eye, will you?'

'Not right away,' says I. 'We'll stay here in the cave a while.'

'All right!' says he. 'That'll be fine. I never had such fun in all my life.'

Wherefore the third person singular?

Answer 1

This is very common in traditional oral narrative—you'll find it all over Twain, for instance, or any British or American folktale collection—and ‘The Ransom of Red Chief’ is presented not as a production by the author but as a story told by the kidnapper ‘Sam’. Note that this non-standard form occurs most often with the verb say, inverted with its subject, and is invariant for both person and number:

Philoprogenitiveness, says we, is strong in semi-rural communities . . .

Says should probably be regarded not as a ‘third person singular’ form but as an almost obligatory fixed discourse marker with the ‘historical present’.

Generalizing beyond say, a little browsing in Google Books suggests that in actual speech (as opposed to literary imitations like this) nonstandard extension of the -s form to other persons and numbers is most frequently encountered specifically in present-tense narrative; but I’m not prepared to assert positively that it is in fact a narrative marker.