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.
The late Daniel Cassidy, in his etymological hoax, How The Irish Invented Slang, claimed that the English term natty derives from the Irish word néata. In reality, of course, néata is a relatively late borrowing from the English neat, which derives from the French word net meaning clean, and ultimately from the Latin nitidus. This gave rise to variants in English like netty and natty.
And he is very wrong about the phonetics of néata. Cassidy obviously thought that the phonetic symbol æ is pronounced like the vowel sound in day. In fact, æ is pronounced the way an English speaker of English might pronounce ‘hat’, so his phonetic version suggests that the word is pronounced nyatta, which it isn’t. It is pronounced nayta.
There is absolutely no reason to suppose a connection between the Irish language and the English word natty, except that the English word was borrowed into Irish as néata.