AY, AYE. The word "aye," meaning always (and pronounced as in "day"; connected with Gr. "aei", always, and Lat. aevum, an age), is often spelt "ay," and the New English Dictionary prefers this. "Aye," meaning Yes (and pronounced almost like the word "eye"), though sometimes identified with "yea," is probably the same word etymologically, though differentiated by usage; the form "ay" for this is also common, but inconvenient; at one time it was spelt simply I (e.g. in Michael Drayton's Idea, 57; published in 1593).
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)