Hey, personally, I think a usage being informal doesn't mean being incorrect (as well as being correct -- it is just "informal"

)
Some Linguists' opinions:
From Merriam-Webster Online Dictionary:
real
Function: adverb
: VERY <he was real cool -- H. M. McLuhan>
usage Most handbooks consider the adverb real to be informal and more suitable to speech than writing. Our evidence shows these observations to be true in the main, but real is becoming more common in writing of an informal, conversational style. It is used as an intensifier only and is not interchangeable with really except in that use.
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(From AHD)
real
adv. Informal
Very:
I'm real sorry about that.
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From Cambridge Advanced Learner Dictionary:
real
adverb MAINLY US INFORMAL
very:
I like this homemade lemonade, it's real good!
It's real easy to do.
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Kenneth G. Wilson (1923-). The Columbia Guide to Standard American English. 1993.
real (adv., intensifier), really (adv.)
It is quite clear that the adverbs real and really are not interchangeable: a real good time (simply "very good") and a really good time ("unquestionably good") are not the same thing. Real is in fact either an adjective (a real blizzard) or an intensifier (a real bad cold). As an adjective it is of course Standard, but the intensifier is Intimate or Casual at best, and most Standard users consider it Nonstandard and characteristic of Common or Vulgar English. It does however have wide Conversational use, and writers frequently adopt it as another evidence of the sound of living speech.
Really is the Standard adverb, and the difference between the intensifier and the adverb is grammatical and occasionally semantic: He is a really distinguished man could mean either that he is very distinguished or that his distinction is genuine, not doubtful. He is a real distinguished man means just that he is very distinguished; no question has been raised or answered about whether the distinction is there or not?-real is just an effort to underscore its presence, unless intonation or punctuation make it unquestionably an adjective.
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