etymology - What are the origins of the regional pronoun “yinz” of southwestern Pennsylvania?

A common informal word used in southwestern Pennsylvania and the forefront example of what is commonly known as "Pittsburghese" is the word yinz, pronounced /jɪnz/ in IPA.

Alternatively it is less commonly used in long form, youins, pronounced /ju.ɪnz/.

To use it in a sentence would be similar to the y’all used by southerners when addressing or questioning an unnamed or understood group of people informally in a sentence.

Are yinz comin’ out to our place before we head to the Steelers game?

Are y’all coming to the speedway for the NASCAR race?

As a native of Pittsburgh, we proudly use this word in conversation despite the seeming confusion and disdain that outsiders seem to have for this word. Two separate friends, one from Boston and one from Brooklyn, both criticize me when I use the word as well as other common regional differences like “this task needs finished” or “I left the warsh rag by the sink”. They say it makes me sound unintelligent and that I should teach myself to lose regional diction for the sake of my career.

I was often curious about the origins of the word. With southwestern Pennsylvania being an old melting pot of the original English, Scottish, and Irish settlers and the Italian, Polish and Slovak immigrants coming to work in the steel mills, I have heard from Italians that it came from the Polish, while the Polish claim it was from the Italians (I am mostly Italian and Polish by blood so I have both cultures in my family). Others still claim it was a derivation of African-American slang that everybody picked up because all of these different peoples worked closely in the same factories and mills.

Is there an official analysis on the origins of this word, or is a mystery to be lost in cultural history?

Answer

Wikipedia says the Irish did it:

Crozier (1984) suggests that during the 19th century, when many Irish speakers switched to speaking English, they filled this gap with you ones, primarily because Irish has a singular second-person pronoun, tu, as well as a plural form, sibh. The following therefore is the most likely path from you ones to yinz: you ones [juː wʌnz] > you'uns [juːʌnz] >youns [juːnz] > yunz [jʌnz] > yinz [jɪ̈nz].

Their citation is:

Crozier, A. (1984). The Scotch-Irish influence on American English. American Speech 59: 310-331.

In this lecture starting at about 19:58, Barbara Johnstone, Professor of Rhetoric and Linguistics at Carnegie Mellon University, also suggest the "you ones" origin. (The first several minutes of that lecture give more background on the immigration patterns that shaped language in Pittsburgh.) h/t Paul Placeway for pointing out the video to me.

I grew up (and still live) in Pittsburgh and I remember yunz being more common 30-40 years ago, though yinz seems to be more common now.