"There's" Before a Plural
Here’s another thing I can’t help but wince at, even though I know grammar wincing is pointless:
There’s a lot of people outside.
I don’t know how I got so invested in the idea that that should be There are a lot of people outside. But I, unwisely, let it rub me the wrong way every time I hear “there’s” before a plural.
Here’s the idea:
There’s is a contraction of “there is.” Is is singular. It goes with a singular subject, the dog is, versus are which is for a plural subject, the dogs are.
Sentences like There is a dog outside or There are dogs outside are kind of special. Notice that the grammatical subject of both is there. So theoretically the verb shouldn’t change. But in fact, these sentences are unusual. In There is a dog outside, there is functioning as a pronoun, but the real intended subject of the verb isn’t there. It’s dog. This sentence really means “A dog is outside.”
Grammarians label this “the existential there.” The word there is the grammatical subject and dog is something called a notional subject. It’s sort of the intended subject even though it’s been upstaged from the subject position by the pronoun there.
In these sentences, the verb is supposed to agree with the notional subject. So There are dogs and There is a dog are both correct because the verbs match the notional subject.
But over the years, there’s has become a handy shorthand for either there is or there are, especially when the next word to follow is some modifier like a lot, which has a singular flavor.
That's why There’s a lot of dogs outside sounds much better than There’s dogs outside.
Either way, though, you can get away it: “Like other grammatical subjects, [there] often determines the number concord, taking a singular verb even though the notional subject is plural” says the Oxford English Grammar. “This usage is common in informal speech.”
In other words, I should loosen up a bit on this one.