How many of you have heard accents that insert a(n) /ɹ/ in to words that end with -ɑʃ, mainly wash for wɑɹʃ.
Are there any theories about why r's are inserted here?

I've noticed a lot of people in my area (Appalachia) who do this. I have no idea why, though.

It's a feature associated with the Southern Midland dialect of American English. My father's family from Baltimore had it, and you hear it occasionally in St Louis, which is an island of Northern Midland speech in an otherwise Southern Midland-speaking area.

As for its origins, here's what UPenn linguist Ben Zimmer has to say: "[T]he South Midland pronunciation of "wash" as "warsh" ... supposedly developed as a hypercorrection resulting from the non-rhotic Southern pattern's loss of prestige. When the rhotic pattern became prestigious in the region, "war" changed from [wO:] to [wOr], and some speakers added r's to other forms like "wash"."

I've heard it. Rather stereotypical of Baltimoreans.

Linguoboy, thanks for the explanation, that makes perfect sense.

My father's family is from the southern United States and they all, including my dad, who has lived in California all of his life, pronounce it warsh. My sisters and I pronounce it wash. I was wondering if the reason my dad got that "correction" was because his whole family talks like that but I didn't get it because my mother has a General American accent (Well my dad's is almost General American except for this) as do most of the people where I live including the workers at the daycare I spent my early years.

Sorry for my rambling, I'm not really sure what I'm asking if anything.

You normally pick up features from your peers, not your parents. What kind of community did they live in? On the one hand here were enough "Okies" moving to California in the early part of last century that they formed their own communities, but their accents tended to be stigmatised so status-aware members would seek to shed them at the earliest opportunity.

It's a perfectly nice link, but I haven't a clue why you posted it. It's not that the OP doesn't know what it is, he doesn't know why it's there.

My mom has always said it, and she's from Illinois. I grew up hearing that my shirt is in the "warshing machine" and that we are going on a trip to "Warshington D.C." Good times.

Is she from East St. Louis?