Duo offers an alternative translation, "It is my population," which is absolutely non-standard English. The best English equivalent I can come up with is "It is my community," which Duo rejects. It should be accepted, and probably so should "It is my group." "Un popolo" is a common group, a community of people.
xyphax's comment is correct, about the difference between "popolo" and "gente," which does not have the same sense of a closed group.
JuveJay correctly points out that "He is my [kind of] people" (or "he is [good] people)" is acceptable colloquial US English, but that construction does not adequately translate the given Italian.
It is possible to say "It is my people (who are being persecuted)," but without that or some other qualifying context "It is my people" is not grammatical English. The given translation, "These are my people," is fine, and it points out the differences in usage between Italian "popolo" and English "people."
After all, the Italian usage is what we want to learn, vero? Now we have; the real difficulty is to remember it.
I am a native English speaker, so just a guess .. from looking at the two definitions I would say that popolo means a people connected by community somehow, gente seems more generic: just people grouped together for a various reason.
As far as I understand it, gente is the most direct translation for the english word "people" as in: "The people are happy" while popolo refers to "the community of people living in a country" in its basic meaning. So in: "The peoples of the world founded the UN to keep peace" one would use "I popoli del mondo..."
In English, "people" has two distinct meanings:
- people₁ (singular), peoples (plural) = nation, nations or group, groups
- person (singular), persons/people₂ (plural) = individual, individuals
So the Italian sentence can be directly translated:
- È il mio popolo = It is my people₁ (nation/group)
"è" is the third person singular of "essere". Third person is "he is, she is, or it is". Italian does not have a neuter gender, so it has nothing to do with being an object. It has to do with being singular or plural. "Il popolo" is singular even though it refers to "people". It is a collective noun. We have them in English. "A group", "a pair", "a set", etc. are all singular but refer to more than one thing. So "Il popolo è" translates as "The people are" because of a quirk in English. "People" is one of the few (only?) collective nouns in English that is plural.
Wow. That sounds so incredibly wrong to my ear that I think the nuns who taught at my elementary school would be horrified. Just one more reason why English is an very difficult language to learn.
That would make the concept of singular collective nouns in Italian even more strange to an English speaker from the UK, but that is what is going on in this example.
"These" came from twists of English. Originally "people" was only singular and meant "nation" or "group of people". There is even a plural of this meaning: "peoples". Later "people" mostly replaced "persons" as a plural of "person". Thus technically you can use any of the two meanings with its implied number:
- È il mio popolo = This is my people
- È il mio popolo = These are my people (used much more often)
You can read more about this in other comments here.
That's not the meaning though: it's confusing in English because "the" is an article for both singular and plural, and people can mean "persons" (plural people) or "population of a nation" (singular, plural peoples). "Popolo" means the latter, i.e. "Italians are a people" -> "gli italiani sono un popolo" (the singular Italian people), versus "the Italians are people" -> "gli italiani sono persone" (the plural Italian people).