Where are you going?The historical source is usually presumed to be all those Germanic languages that have such constructions -- German ich komme mit, etc. That would be a pretty simple extension of English verb + particle constructions (or whatever they are ultimately) like to come to, so a pretty minor (if salient) change.
To the store. Wanna come with?
A lot of folks have talked about exactly what verbs can appear in the 'come with' construction -- the core context is verbs of motion, clearly: bring with, take with, go with, run with.
It can also appear with to be in forms like in this hypothetical phone call:
Oh, you're in the Dells? Are the kids with?This would also translate into my dialect with along -- although the result doesn't sound quite right even then. That suggests that it's getting at accompanying somebody during motion, not the actual motion itself. Then a few weeks ago, a Wisconsin English Project team member reported that at a hockey game, his team (NOT his line, he was at pains to add) was not playing aggressive defense at some points, which means that people were not all sticking on their opponents like glue the whole time the puck was in their zone. A teammate (a defensewoman) yelled to those on the ice: Stay with! Stay with! He reports that he's since heard it again from other players and that there's no way there's an object pronoun getting lost.
But it gets wilder ... according to that same person, South African English is reported to have the construction too, regarded as coming from Afrikaans. Here's a quote from his email about this:
In looking for something entirely different, I got this on wikipedia and by the time I got to hey as a tag question, I was left wondering if this was a piece of wikiality (which I imagine is Colbert's best candidate for Word of the Year this time around).Man, if those South African English facts are right, I think I love language change even more than before.
In fact, they have ja (vowel of 'father') too, so this written text is ambiguous between Wisconsin (Minnesota, etc.) and South Africa:
Are you coming with to the movies?
Update, Friday, Sept 29: Word is that a linguist with lots of experience in South Africa has orally confirmed that these features are found in South African English, save for the hey -- which he happened not to remember offhand.