I met this in the reading of "The Autobiography and Other Writings of Benjamin Franklin" as follows:
"I will be rowed home, says he. We will not row you, says I."---from the chapter "First Visit to Boston"
Similar question regarding third person singular is "God bless you" that also puzzles me much, I think the correct form should be "God blesses you".
Tag question like "I am your father, aren't I?" is also interesting, why "aren't I" but not "amn't I", because "aren't" is apparently the short form of "are not", but not correct for the matching when the subject is "I".
Please explain, thanks.