If you mean Yinzer, it apparently refers to a Pittsburgh local whose accent is local to that area.

YMMV

'Yinz' is a regional colloquialism for the second person plural pronoun 'you.' It's the Pittsburgh version of 'y'all' (which I much prefer over my native alternative). It's based in the Scots-Irish dialects and can be found in various forms from eastern Pennsylvania all the way down the Cumberland Plateau into northern Tennessee. 'Yinzer' is the affectionate term (adopted by and possibly also coined by) for people from the Pittsburgh area, particularly those who--as Ron has suggested--have rather notable accents.

Down in the Pennsyltuckey area (Pennsylvania, Kentucky, parts of southeastern Ohio, and West Virginia), that same word ends up as "Y'uns". As in, "what're y'uns doing?"

Sounds like it only changes a bit the further south you go.

Frightening...

Yinz sounds sort of like an extreme contraction of "you'uns" that folks in the mountains of East Tennessee use instead of the "y'all" that the rest of the state uses for "you, plural".

That's exactly it. Depending on the region, it is pronounced "yunz," "yinz," or "you'uns." A cultural anthropololgist I know in the Crossville area explained the background behind it. I don't, however, believe that it's directly related to the "yous" of the Philadelphia/New Jersey region (and New York?).

For the "yous" types in the aforementioned Philadelphia/NJ area, it's probably not related. It's because they're a bunch of inbred, knuckle-dragging, momma's boys incapable of forming coherent thoughts.

Philadelphia sucks. Jersey also sucks.