If you listen carefully to the speech of country people you'll hear echoes from the distant past. I was reminded of this fact by a letter from a Kilkenny schoolboy who doesn't want to be named, but who is intrigued by the prefix a which he hears continually around him. This a represents the Old English preposition on, and my young friend's examples are: "He was here a Friday", and "Her house went afire". An interesting example is found in the Antrim adverb alow, on fire. "The chimley's alow" is given in that wonderful book, The Ballymena Observer, published in 1892, and well worth a reprint. Here we have a on, and low, from the Old Norse loge, a flame, a blaze.
The south-east Wexford adverb amain, strongly, at full speed, also contains a, representing Old English a-, earlier ar-, originally implying motion onward, hence used as an intensive prefix. "The work is going on amain, and the house will be roofed before the Christemas", said old Jack Devereux of Kilmore Quay to me once. (Main from Old English maegn, force, power. "Cry you all amain, "Achilles hath the mighty Hector slain". wrote your man from Warwickshire in Troilus and Cressida.)
Jane Barlow, a poor enough novelist who flourished at the end of the nineteenth century, but whose ear for dialect was acute, used a as a prefix of state or condition. Her Bogland is set in the west, and there she heard, "The air was a-ffluther wid snow", and "When th'ould master had tore it wid his hands all a-shake..." She used a with the verb to be to form continuous sense: "I'm a-thinkin".
In Wexford and Kilkenny a is used for the preposition with: "She's adin', within' adout, without, outside. This is general all over England, except that they pronounce the words athin and athout.
Indeed, all these examples are common across the water still, as is the use of a as the indefinite article before numerals and nouns of multitude and quality. All over the south and west of this country I've heard such as, "There's not a one of to-day's hurlers who could hold a candle to Ring". This was said to me the other night by a great Tipperary hurler of yesteryear, reminding me of Shakespeare's Macbeth: "There's not a one of them but in his house I keep a servant fee'd", and Chaucer's "And up they rysen, wel a ten or twelve". Keep listening and you'll hear the echoes.