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.
This is one of the many cases where Cassidy simply claims (or implies) that because there are similar words in Irish and English, the source of the word must be the Irish version. This ignores the fact that the movement of words between the two languages has mostly been the other way, from English to Irish, and that mam(my) goes back further in English than it does in Irish. The term mam(my) seems to date back well into the sixteenth century in English, while in Irish there is no evidence of it before the modern era. (Though there is a word for a fostermother or nurse, muim(m)e, which dates back a long way in the language.) To be perfectly honest, I can’t claim to have exhaustively researched this matter but the earliest use of it I can find (in the form maimín) in the Irish-language Corpas na Gaeilge dates back to 1803.