“Needs washed” is commonplace in NE Ohio, too, to the degree that I’d say it is interchangeable with the two other forms (i.e., needs to be washed, needs washing). I’m fairly well-educated and consider myself to have an above-average grip on proper English grammar and punctuation, but it took me a few minutes to understand the wrongness of this “needs washed” construction (I hope because I’ve been so exposed to it). It doesn’t sound strange to me when spoken, nor look strange to me when written, and I’m sure I’ve said it myself (I’ll have to stop that, especially now that I’m in Michigan where it apparently isn’t used, especially by the “educated,” among whom I associate). “Warshed” (as well as “bathed,” pronounced with a short a sound, and “striped,” pronounced to rhyme with “biped” as opposed to “wiped)” are looked down on as being an uneducated way of speaking by most North Eastern Ohioans, and typically associated with people from extremely rural areas. “Warshed” makes me cringe, and I have never said it except as an example in a discussion of its incorrectness/annoyingness.
I have nothing further to offer about the origin, but I would second what **Chessic Sense **about it’s functionality; it does offer a distinction between a desire to be engaging in the act (the car needs washing), as opposed to a desire to have the act done and over with. However, I disagree in that I think this is encompassed with “needs to be washed” (I don’t see how this one implies the ongoing act of washing needing to be done); the only benefit I can see “needs washed” to have over"needs to be washed" is that it’s shorter.
To slightly hijack the thread, is anyone familiar with this one, which is also from NE Ohio/PA (though perhaps not exclusively):
My mom drives bus for the elementary school.
I have to mow lawn before it rains.
Some of our super-rural neighbors would occasionally whip out that construction, and they could not be convinced that they sounded like a cliched Native American in a bad Western. Usually when they’d say things this way, it was in reference to some kind of profession/duty, and proper definite/indefinite articles were otherwise used normally.
Oh! I’ve also heard you-uns is as yous guys, or yous (which I think actually makes a lot of sense when trying to distinguish between one person from a group and the whole group, like the French tu [singluar] and vous [plural or formal]). Sounds kind of hillbilly-ish, but has some functionality.