What is the spelt-out form of “What gives”?

What gives? means:

Inf. What happened?; What went wrong?; What's the problem?

Bill: Hi, you guys. What gives? Bob: Nothing, just a little misunderstanding. Tom's a little angry.

Bob: Where's my wallet? What gives?

Tom: I think one of those roughnecks who just walked by us has borrowed it for a little while.

According to this page on the linguistics of the phrase, it is not short for anything. There are a few theories about how it arose:

Regarding the issue of why what gives is anomalous, the best that I can offer (speaking now as an historical linguist) is to suggest that we turn to the history of the construction, but even there, full enlightenment is not forthcoming (see Joseph 2000 for more detailed discussion). The construction seems clearly to have originated in American English; the first attestation for what gives comes in 1940, in John O'Hara's Pal Joey, according to Wentworth and Flexner (1960: 574, s.v. what gives) and the Oxford English Dictionary (1989 on-line second edition).

Even with this late attestation, what gives makes for an interesting comparison with the German existential use of geben 'to give', in the impersonal form with an expletive subject, es gibt, as in Es gibt keinen Gott 'There is no god', itself anomalous from the point of view of the usual syntax and meaning of geben...

Some scholars however see what gives as having arisen via language contact, as a calque from German, an origin for it which would eliminate a basis for a Proto-West-Germanic prototype, but might allow for a different explanation for the anomalies this expression shows; that is, under such a view, it would show an anomaly because it is a borrowing in the same way that an expression like It goes without saying, calqued from French Ça va sans dire, does, with its unusual passive-like voice semantics for an active form of say. In particular, it has been suggested (Chapman (1986: 463, s.v.); see also Wentworth and Flexner ibid.) that what gives is a loan translation from German or Yiddish was gibt 'What's going on?'.

The site itself has an even more thorough explanation of the phrase. However, it is a phrase on its own, rather than an abbreviation of another phrase. It means "What's happening?" or "What's up?" It is usually informal, though, so you would not see this in formal writing. You can use it in conversation with others, and they will understand you. However, the tone is slightly negative, so be careful when you choose to use it.

I've been living in Germany for 17 years, and this morning the similarity of the phrase "What gives?" to the German "Was gibt's?" occurred to me, so I checked the net ...

The article "What Gives with What Gives?" by Brian Joseph of Ohio State University - also cited above - seems to provide a well founded discussion of the syntax and origin of the phrase in American English. Joseph argues, however, that the German may not be suitable as the origin of the phrase:

… there is no German expression that is simply was gibt! Rather, colloquial German has was gibt es? 'What is the matter? What's up?', but this is not a suitable source for what gives since the putative calquing did not lead to a direct counterpart to the German subject pronoun es (thus, what gives, not *what gives it or *what does it give).

For all us non-linguists out there, Wikipedia says:

In linguistics, a calque (/ˈkælk/) or loan translation is a word or phrase borrowed from another language by literal, word-for-word (Latin: verbum pro verbo) or root-for-root translation.

I believe, however, that his dismissal of the German as a source is flawed, because Joseph is principally arguing from a syntax-of-language standpoint and thus comparing the (written) WORDS instead of the SPOKEN language.

Clearly in a comparison of the SYNTAX of "Was - gibt - es ?" with the English "What - gives ?" the word "it" (="es") is missing in the English. However, back then even more so than today, language is primarily a SPOKEN organism! - and a comparison of the SPOKEN phrases provides a very solid argument for its origin from the German:

In the spoken German phrase "Was gibt es?" the second and third word are slurred together (at least, based on modern-day speech), so that only the "s" of "es" is pronounced (sorry, phonetics here are my best guess):

/vasɡiːpts/ and /vasɡɪpts/ (normally written out with an apostrophe: "Was gibt's")

In comparison to the English "What gives?", we can see (or rather hear) that the transition from the German to English comprises the translation of "Was" to "what" and the minimal change in the consonant sounds /pts/ to /vz/.

The final /s/ in the German becomes the third person inflection "(it) gives" in the English. In other words the word "it" IS implicitly present in the English, but as an inflection of the verb instead of as an extra word.

Wikipedia to the rescue again! Wikipedia explains that:

Calquing is distinct from phono-semantic matching.[3] While calquing includes semantic translation, it does not consist of phonetic matching (i.e. retaining the approximate sound of the borrowed word through matching it with a similar-sounding pre-existent word or morpheme in the target language).

and

Phono-semantic matching (PSM) is a linguistic term referring to camouflaged borrowing in which a foreign word is matched with a phonetically and semantically similar pre-existent native word/root.

So, to summarize:

I argue that the phrase "what gives?" likely originates from the German "Was gibt's?", and transitioned to English primarily due to the phono-semantic match of the two phrases, and that the transition can be described as a calque in so far as the "it" is implied in the presence of the third person singular inflection /s/.

I would be gratified if a linguist would take my argument further, and reiterate it using the correct phonetics.