Yankee: Dutch origins
Most linguists look to Dutch sources, noting the extensive interaction between the colonial Dutch in New Netherland (now largely New York, New Jersey, Delaware, and western Connecticut) and the colonial English in New England (Massachusetts, Rhode Island, and eastern Connecticut). Michael Quinion and Patrick Hanks argue that the term refers to the Dutch feminine diminutive name Janneke or masculine diminutive name Janke, which would be Anglicized as "Yankee" due to the Dutch pronunciation of J as the English Y...Alternatively, the Dutch given names Jan ("John"; pronounced Yan) and Kees ("Cornelius"; pronounced Case) have long been common, and the two are sometimes combined into a single name (e.g., Jan Kees de Jager)... The chosen name Jan Kees may have been partly inspired by a dialectal rendition of Jan Kaas ("John Cheese"), the generic nickname that Southern Dutch used for Dutch people living in the North.
The Online Etymology Dictionary gives [the word Yankee's] origin as around 1683, when it was applied insultingly to Dutch Americans... by the English. Linguist Jan de Vries notes that there was mention of a pirate named Dutch Yanky in the 17th century.
I wonder if the Amish term for non-Amish as “English” is in response to being called “Jannke”
Which reiterates my point! Amen, and thanks! :-)