I noticed this article about Cassidy by Mark Abley in the Montreal Gazette: http://www.montrealgazette.com/life/Watchwords+Irish+really+invent+American+slang/8085048/story.html. It is nice to see that some newspapers have a much more intelligent and discriminating attitude to Cassidy’s work than others which should have known a lot better – The Irish Times, for example, or the Irish News. The article is very balanced and quotes people who know what they are talking about, rather than accepting all of Cassidy’s nonsense at face value. I would just have one word of criticism. The author says that:
Barrett and other critics have pointed out many such flaws, yet Cassidy’s book remains in wide circulation and still has passionate defenders. I suspect his basic point is valid: Gaelic probably does lie at the root of much American slang. It’s a pity that a book making this point so powerfully is also undermined by dubious research and wild speculation.
This is spot on, apart from the suspicion that Cassidy has a point, even if it’s badly made. Sorry, not a chance. There might be some interesting work to be done in the field of Irish influence on the sentence structure of American English (expressions like to hit the road, I wouldn’t put it past him) but if there were lots of American slang words of Irish origin it would be obvious and would be a well-established fact by now. The fact that Cassidy had to invent all his evidence to make any semblance of an argument is a powerful indication that there is nothing to find.
However, check the article out and hats off to the Montreal Gazette and to the aptly-named Mr Abley for telling it like it is.