It’s simply that, in English, there is no indefinite plural article — or, equivalently, that the indefinite plural article is null. So ‘they are doctors’ is consistent with the behaviour of plural nouns elsewhere.

Contrast this with, for example, French, where the indefinite singular un(e) correspond to the indefinite plural des: La boulangerie vend des baguettes ‘the bakery sells baguettes’ (whereas English cannot say *‘a baguettes’). But as in Spanish, professions take no article either way: Il est médecin / Ils sont médecins. So all three languages are self-consistent, just in their own ways.

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hbn 6 hours ago | parent [-]

English still feels hard to explain when things sound natural and when they don't.

You can say "there are some vendors in the street" and it sounds normal. But if you were to say "they are some vendors" it sounds weird. It's pretty firmly more natural to say "they are vendors."

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bradrn 6 hours ago | parent | next [-]

Oh, certainly, as is the case for any language!

In the case you mention, I note that Huddleston & Pullum in their Cambridge Grammar of the English Language specifically call ‘some’ an existential determiner. As is usual with them, this is an insightful observation: you use ‘some <noun>’ specifically in order to say that there exists some set of things drawn from some larger set or in some configuration. You say ‘there are some vendors in the street’ because you’re drawing attention to their existence in the street (and indeed ‘there is/are’ is the prototypical English expression for existentials). You don’t say ‘they are some vendors’, because the use of ‘they’ implies some specific group of vendors already known to both speaker and listener — highlighting their existence again feels weird.

(Of course, this analysis is still incomplete. At some point you simply have to list all the specific ways in which ‘some’ is used — which, indeed, is exactly what Huddleston & Pullum do. Furthermore I’m certain that there is some discourse context in which ‘they are some vendors’ would be natural, even though I haven’t managed to think of one just yet.)

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schoen 5 hours ago | parent [-]

I'm not sure this is the best achievable example, but maybe:

"The street vendors have decided to oppose the ordinance."

"But I thought Mike and Jacob said they support the ordinance. And Julia! Aren't they vendors?"

"They are some vendors, but most vendors take the opposite position."

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subarctic 3 hours ago | parent | next [-]

That one is more natural without the word "some" imo

	▲	schoen 31 minutes ago \| parent [-]
		I agree, so it's still not an ideal example.

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cwnyth 3 hours ago | parent | prev [-]

More simply: "Some vendors support the ordinance, but most oppose it."

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jrmg 4 hours ago | parent | prev [-]

And “they are some vendors” usually actually means “they are excellent vendors”!

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1-more 4 hours ago | parent [-]

Really depends on how you say “some”

	▲	rectang an hour ago \| parent [-]
		I will die on the hill that "SOME PIG" from Charlotte's Web was merely an existential determiner.