The word "Eilleen" appears to be a peculiar spelling of the name "Eileen." The IPA phonetic transcription would be /aɪˈliːn/ which represents the pronunciation of the name. The "ei" in "Eilleen" is likely an attempt to represent the "ee" sound within the name. However, the traditional spelling of "Eileen" is more widely recognized and accepted, and would be recommend when using this name. It is important to use proper spellings, as it avoids confusion and allows for clear communication.
The etymology of the name "Eilleen" is uncertain. However, it is believed to have originated as an anglicized form of the Irish name "Eibhlín" or "Eibhlinn", which itself is a variant of "Aibhilín" and "Aibhlinn". These Irish names were derived from the Norman-French name "Aveline" or "Avelina", which evolved from the Germanic name "Avelina" or "Aveline". The Germanic name is believed to have originated from the element "avi", meaning "desired" or "wished for". Therefore, "Eilleen" ultimately derives from the Germanic name "Avelina" and has its roots in the Old German language.