The first word in English dictionaries, of course, is "a": as the article, as various abbreviations, and as the letter itself. Some dictionaries note that "a" can also be an informal or dialect form of "of" or "have." But not even the OED, which devotes several pages to the many dialectal and historical meanings of "a," notes that it is also sometimes used as the preposition "to" and the infinitive particle "to."
All four of these usages appear in dialog in Annie Proulx's short story "The Trickle-Down Effect," which appeared in the New Yorker of December 23 and 30, 2002. The speakers are contemporary residents of rural Wyoming and Wisconsin.
"Never mind. What can I do for you? I'm kind a busy."
"Must be full a weeds and thistles."
"I could a sold it at the hay auction for more, but Deb said you was a friend and needed hay bad."
"Givin' up farmin'?" "Yeah. Goin' a film school at U.C.L.A."
to (infinitive particle)
"Sooner the better. I want a get out a here."
"You know I'm goin' a bite your red rosy ass with a heavy price."
"Shouldn't take you more'n a few weeks a git her done if you work at it steady."
(February 28, 2003)