For some time now, some of my on-line friends have advised me to provide a version of CassidySlangScam without the invective aimed at Cassidy and his supporters. In response to that advice, I am working on providing a glossary of the terms in Cassidy’s ludicrous book How The Irish Invented Slang with a short, simple and business-like explanation of why Cassidy’s version is wrong.
Etymology is not always easy or straightforward. Words often have complicated, difficult histories.
One such word is the English gab, meaning talk, chatter, loquacity. This probably comes from an Old Norse source, either directly or via Old French gap, gab, which means joke or jest or bragging talk. There is also influence from Scottish and northern English gab, meaning the mouth, which could be linked to Irish or Gaelic gob. Some people think that it is linked to gabble and is maybe onomatopoeic.
There is an Irish word geab (and a Scottish Gaelic gab). These words are probably not old and are probably borrowings from English or Scots (though giob-geab is recorded from a long way back in Irish with the meaning of ‘chit-chat’).
Daniel Cassidy, in How The Irish Invented Slang, assumes that the movement was the other direction, that gab originates in Irish and then enters English and Scots from there.
His treatment of sources in this case is worth examining, as it is more dishonest than most entries in Cassidy’s book. (Almost all of which are quite dishonest.)
“Some Anglo-American dictionaries derive the English gab of chatter from the Old Icelandic gabb, gabba, meaning “mockery”. … Professor MacBain associates Gaelic gab with Irish gob, a beak or mouth.”
I am not aware of any Anglo-American dictionary deriving gab from Old Icelandic. Some sources mention Old Icelandic as a cognate. MacBain does NOT associate gab with gob, as you can see if you click on this link:(https://en.wikisource.org/wiki/An_Etymological_Dictionary_of_the_Gaelic_Language/G)
MacBain gives a Middle English origin for gab and then says cf. gab in his entry on gob. At no point does he state or imply that gab actually comes from gob.