Most dictionaries regard yack and yacking as versions of the phrase yackety-yack. In other words, they are an onomatopoeic rendering of the noise a set of teeth make when they are chattering. In Daniel Cassidy’s outrageously stupid book, How The Irish Invented Slang, Cassidy suggests that it comes from the Irish éagcaoin (properly éagaoin), which is pronounced aygeen and means ‘mourning’ or ‘lamenting’. This is really not similar at all, either in sound or meaning and of course, there is no evidence of yacking having an Irish origin. It is just bullshit and nonsense, like everything else in this book.
I came across a really funny quotation from Cassidy the other day in an article called Family History and Irish America, which is by someone called Marion R. Casey and published in The Journal of American Ethnic History (remind me to cancel my subscription!). She is apparently a genuine academic, though her impartiality is suspect (as well as her common sense) because she is linked to Professor Joseph Lee at NYU, who is on record as supporting Cassidy and endorsing his duff research as though it were a real and valid contribution to the sum of human knowledge. Anyway, I will quote it below:
“Ireland will take care of itself. My advice to students who are into Irish studies, or into any studies that look at America, and who want to come into an interesting field, and a field that will open up – you know, there are not a lot discoveries being made in the Humanities these days, folks! You come into Irish American Studies and there’s a lot of them. They’re like big gold nuggets sittin’ on the ground so get out there, start pickin’ ’em up.”
This is (unintentionally) rather funny, when you consider that the stupid claim above and hundreds like it are among Cassidy’s ‘nuggets’. The image of gold nuggets is very apt, given that gold nuggets often turn out to be fool’s gold, and that fairy gold which turns out to be worthless is a cliché of Irish folklore. But the strongest image it evokes in my mind is Cassidy the madman, squatting down and producing another fresh ‘nugget’ which he then holds up proudly to idiots who should know better. ‘Dat’s right. It might look like shit but I can assure you dat’ it’s pure gold. I’ve laid a whole lot o’ dem. And my ass is a p’fume factory too.’