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.
It seems likely that spon is simply a contraction of the English slang term spondulicks. Daniel Cassidy, in his etymological hoax How The Irish Invented Slang, regards it as deriving from the Irish word sparán, meaning a purse, because spondulicks, according to Cassidy, derives from an ‘Irish’ phrase sparán tuilteach. While the origin of spon and spondulicks is unknown, sparán and spon do not sound similar and the claim is very unlikely.