Re: He's telling us there's a whale out there for us. - Is "out there" an adverbial?
There is a shark out there.
Further to my previous post, I would ask what you mean when you say: "There is a shark out there" derives from "A shark is out there".
Surely the speaker does not go through some silent process in their mind of thinking "A shark is out there" and then converts that to the spoken "There is a shark out there".
I mean "derives from" in the same sense that "Is there a shark out there?" may be said to derive from the string "there is a shark out there."
What evidence could you have for such a claim?
Subject-verb agreement is a good source of evidence. Dummy-"there" (or existential-"there") subjects do not determine subject-verb agreement. Compare:
(a1) There is a shark out there.
(a2) *[strike]
There are a shark out there[/strike]
.
(b1) There are sharks out there.
(b2) *[strike]
There is sharks out there[/strike]
.
Those sentences illustrate that dummy "there" can be followed by a verb in the singular or in the plural. The choice between the singular or the plural is constrained by the noun phrase that comes after the verb.
Therefore that noun phrase is the underlying subject. Sentences with dummy-"there" subjects derive from their dummy-less counterparts. In transformational-generative frameworks, the relevant operation has for at least half a century been known as There-Insertion.
I saw a shark out there.
Again, I would ask what basis there is for saying that "a shark out there" is a clause. It looks to me as though you're assuming a markedly different theoretical framework to mine.
I think reflexive pronouns offer a good enough basis. As you know, reflexive pronouns in their normal, non-emphatic use require co-reference with the subject of their most local clause. Consider, then, the following sentences:
(c1) I saw a shark out there by itself.
(c2) ?? I saw a shark out there by it.
(d1) I saw a shark out there by myself.
(d2) ?? I saw a shark out there by me.
It is obvious that (c1), with the reflexive pronoun "itself," is needed to indicate that what the speaker saw was the shark out there by itself, i.e., all alone. In sentence (c2), "it" does not refer to the shark, but to some contextually unspecified thing or animal next to which the shark was when the speaker saw it.
In (d1), the reflexive pronoun ("myself") refers back to the subject of the main clause. "I saw the shark out there by myself" indicates that the speaker saw the shark with his unaided eye. In sentence (d2), by contrast, "by me" has a different significance, one too weird for me to want to paraphrase.