Etymology of "to be like" meaning "to say"

It seems that "to be like" is an informal phrase for "to say". E.g.

She was so angry, she was like "I'm breaking up with you", and I was like "I'm sorry", and she was like "Go away".

Is this a recent thing? When did "to be like" start to be used to mean "to say"? It doesn't seem to be in any dictionaries (yet) (I might be wrong, though).

It would be interesting to know why the words "to be like" came to mean "to say", although I realize that the answer to the majority of "why" questions is "just because".

Solution 1:

The OED’s earliest citation is dated 1982. It is from Frank Zappa’s song ‘Valley Girl’, which has the line ‘She's like Oh my God.’ The entry is for to be like, and it is described as colloquial and of US origin and as being ‘used to report direct speech (often paraphrased, interpreted, or imagined speech expressing a reaction, attitude, emotion, etc.); to say, utter; (also) to say to oneself.’ A further note says

Often used to convey the speaker's response to something, or to introduce segments of an ongoing conversation between two or more speakers. Sometimes also used to introduce a gesture or facial expression evocative of the speaker's feelings.

Solution 2:

As someone who used to be among native speakers of that dialect...

There are many usages that are getting conflated in the other answers here:

1. Like, he was mad at me, man.
2. He was, like, 'I am so mad!'
3. He was, like, mad at me!

You're only asking about usage 2. In this case like isn't acting as a discourse particle--it most definitely is not standing in for 'um' or 'err'. (That's use 1, which is a much older usage.)

It acts (acted?) as a non-specific way to introduce a third party's contribution to a conversation: the speaker is not necessarily quoting them directly, but instead is communicating the intent of what they said. He said, 'I am so mad!' would communicate something different--that that is what was actually said. In this case, the speaker means that what he said was 'like' (similar to) 'I am so mad', but not actually that.

Usage 3 is more about using the word as a community-defining shibboleth.

But hey, usage probably has shifted in 30 years.

Solution 3:

Since I am all too frequently faced with this at work, in an American middle school, I should point out out that while it does double for the ubiquitous um, it also means that they may be paraphrasing. In other words "I don't remember what he said but he meant go away"