Nevertheless, they're interesting. Some I can agree with, some I can agree with but only up to a point, and some I can't agree with at all. Word derivation is too complex to be left only to the OED, Webster's, and that herd of ilk, and offered alternatives should be carefully considered before being rejected.

A cognate or an echoic word is always possible, but I'd want to see more evidence besides Cassidy's "it has to be this because: derivation unknown." It's also possible that someone was working with something and said, "Hand me that...that...that...that gizmo over there."

I am not by any stretch an Irish speaker (hopefully I'll know more in three weeks or so) but when I showed Cassidy's book to relatives-by-marriage who ARE native speakers of Irish they said that some of the derivations are certainly possible. And Cassidy is correct: many native Irish speakers did end up in the US, including my wife's grandfather.

(My folks came from either the Netherlands or Germany, depending on who won the war.)