I first encountered adding an "a" before a verb in songs in phrases such as "I've been a-playing". At first I thought that songwriters add it when they need one more syllable to make a verse sound right. Then I thought that this may be some kind of a Texas dialect or slang.
But I also saw Charles Dickens using that: "and all mostly sounded as to be a-talking to theirselves, or a-passing blame on the t'others, and not a-talkin to us" and I'm confused.
Why would anybody speak like that and how formal/informal is it?
