I was wondering about this point about dialect. At what point does something become dialect rather than a grammatical error?
If they're trying to use formal, textbook grammar, it's an error. Otherwise, it's dialect. Well, dialect or your own idiosyncratic form of speech, anyway.
You only need to see how many people write "they're" when they mean "there" or "their", or vice versa. What do they think the apostrophe in "they're" represents?
I've noticed I even do that myself sometimes, though. I don't think it's through any failure to understand the difference (well, it might be in some cases, but I'm pretty sure I know which spelling is which!}. It's just that your conscious brain isn't fully briefed in everything going on while you're typing - especially when half-asleep at work. I think you just subconsciously make a phonetic connection between the sound and one of the spellings without any real awareness of what your fingers are doing.
Lastly - to those complaining about 'at all' - what's the issue? We can't go getting rid of speech patterns simply because they add nothing to the meaning of a sentence. We keep them to give our speech rhythm and style.
"D'you want owt from the shop?' has a different feel to 'D'you want owt from the shop, at all?' It doesn't matter if the meanings are identical.