In Old English the first-person, personal, singular pronoun was ic (today it is I). It was probably pronounced something like each. By the 12th century ic was already I (but I don't know when ee became eye).
Interestingly, probably due to the remoteness of village life, traces of ic seem to have persisted until the 19th century.
In Thomas Hardy's 19th century novel about rural life in Wessex, The Woodlanders, there's an old woman who uses " 'ch " for "I": link
"Can't abear it! No; I wanted to see you, Miss Grace, because 'ch have something on my mind....'Ch have been going to ask him again to let me off, but I hadn't the face."
This wasn't only an effect created for a book. In 1889 Hardy mentioned that this dialect still existed: "This & kindred words – e.g. – “Ich woll”, “er woll”, &c, are still used by old people in NW Dorset & Somerset . . . I heard “Ich” only last Sunday; but it is dying rapidly. I know nobody under seventy who speaks so, & those above it use the form only in impulsive moments when they forget themselves’."