When Americans say something like, "Are you mad at me?", is there any difference between that and, "Are you angry at me?"
To me, as a Brit, 'mad' means 'insane'. Saying, "Are you mad at me?" should indicate an even greater state of anger than usual, such that it actually drives the person insane.
The usage of mad to mean "insane" is considered a Briticism in America—go figure. Yet mad is actually a very diverse word. As an adjective, mad can mean insane, furious, rabid, wild, frantic, even hilarious. The use of mad to mean "beside oneself with anger" dates back to the 14th century. Rev. John Witherspoon, a Scottish-born signatory of the Declaration of Independence, dismissed that usage as an "Americanism" in 1781. I guess we Americans have ourselves to blame.
I would say the British can use Mad as a synonym for angry – at least locally. According to the OED:
6b. Angry, irate, cross. Also, in weakened sense: annoyed, exasperated (with †against, at, with, etc.). Now colloq. (chiefly N. Amer.) and Brit. regional.
As a native Brit, I frequently use Mad to mean both Angry and Insane... particularly when I am at work(!).
I don't think there is much of a trans-Atlantic distinction in meaning.
To answer the question, my own American sense of 'mad' vs. 'angry' is that 'mad' is a mild form of 'anger'. If I'm mad at someone, it's a low degree of anger, greater than 'annoyed', but less than outright 'angry'. After 'angry', would come 'really mad'. Then perhaps, 'livid' or 'furious'.
Edit: I also think that perhaps they carry different time frames with them. 'Mad' is more temporary and might be expected to fade sooner.
You cannot call that as a nasty corruption. Because, the word mad, with the meaning of angry, belongs to American English. A word or phrase of one dialect may sound weird/incorrect for the other.
As a matter of fact, mad to mean angry is still a regional word in UK.
An update on the usage of 'mad'-- Beginning in California and moving eastward across the US we have 'mad' as an intensifier: She was mad funny! That was mad crazy. The guy is mad stupid.
American children usually say “mad.” American adults generally say “angry,” and are likely to know the difference. A right-wing millionaire here in Texas had a radio campaign in the 1970’s that went, “I’m Eddie Chiles, and I’m mad!” He was, of course, angry about what he perceived as left-wing nonsense, but in his case, maybe he was so angry that it bordered on insanity.
Of course, Americans also use mad in its more traditional sense. A mad dog is a rabid dog, a madman is a lunatic, a mad cow has BSE, and madcap means pushing the edge of reason.
As a kid I would use the word mad when I was disturbed. As an adult I've moved towards using it more for mental state; insane.
