I believe it could be left out and keep the general meaning. To my ear*, Это kind of reinforces the "identity" aspect, in the sense that that you're sort saying "I am indeed that exact person" or "I and he are synonymous".
Make no mistake, it's a very weird sentence, and my sense is that it is only at home in literature or drama.
- Born in the US to native Russian-speaker parents.
It should certainly be accepted, seeing that many of us have been programmed by teachers or parents to produce and accept this or similar phrases, such as 'It is I / he / she." However, is there anyone among us, who, when pointing to himself or herself in a photo, would actually say: This (person) is I! ????
"Is" is a linking verb that describes a state of being; it links the subject and a predicate nominative term.
You wouldn't say "who is him?" You'd say "who is he?" In "who is he?" and "I am he," he is a predicate nominate pronoun, not the object, and so takes the nominative form.
Let's expand the predicate: "Who is this phone call for?" "I am he for whom the telephone tolls!"
he is a predicate nominate pronoun, not the object, and so takes the nominative form. → that is incorrect. The complement is indeed sometimes called predicate nominative (=predicate noun). The term means that the complement is a noun or a pronoun.
Well, yes, it is.
What? English grammar structure is: SVO.
subject - verb - object
- I is the subject - 'the performer' of the action (it even has specific form of 'to be' verb: 'am')
- am is the verb
- him is the object
Comp. I am not her. She is not him.
There is no SVS in English.
It's me. vs. It's I. is about something else. It is the dummy pronoun in the both sentences (the same like e.g. It's raining. )
So speakers (or their teachers) decide whether the artificial pronoun or the personal pronoun is the subject in the sentence.
But the sentence: I + verb + smth is SVO.
As a native US English speaker, I use pronouns in the nominative case after the verb of being in some instances more than others. For example:
1) The phone rings. John picks it up and says, "Hello"? The caller asks, "May I speak with John Doe"? John answers, "This is HE. But, really you should speak with Judy. It is SHE who knows all the answers."
2) Hey! Is that the guy? Oh yeah! That's HIM!
The first example follows the rule, while the second does not. Both are commonly heard. Like most languages, English grammar is consistently inconsistent. But, first learn and use the rules, then the exceptions... not the other way around Besides, compared to Russian, learning English declensions is a breeze!
If you wish to delve deeper into controversies and history about the use of pronouns by Americans, wikisource has The American Language/Chapter 41 (H. L. Mencken) on line.
The problem here is the generations of teachers who learned and later taught their students the lie that it is somehow incorrect to say "It's me" in English because in Latin the verb "to be" puts both nouns into the nominative, e.g. "Marcus agricola est."
Different languages use different patterns:
Spanish: "Soy yo" (Literally, "am I" = "I am").
Russian: "Это я" (Literally, "this I" = "It is I").
French: "C'est moi" (Literally, "It's me").
English follows same pattern that French does. To see this, get away from the often-corrected "It is I" (which is obviously not really English because it doesn't contract "it" with "is"). You and a family member arrive home and start to come in the door. So as not to startle the ones in the house, would you call out "It is we" or "It's us"? Or consider the excellent example mentioned in the comments above, when you recognize the thief running down the road, would you call out "That is he!" or "That's him!"?
A linguist follows what's called a descriptivist approach to a language: He describes it as its speakers actually use it. The opposite is called a prescriptivist approach: Telling native speakers that their natural intuition about how to use their own language is somehow wrong and that they should follow an unnatural pattern that somehow seems more "correct" in the mind of the prescriptivist.
It's sad when small children show better intuition into the nature of their language than do their elders who correct their speech and confuse them.
I tell people that when they can convince a Frenchman that he really should say "C'est je" instead of "C'est moi," then I'll consider that I really should say "It is I" instead of "It's me."
Like quite a few Romance languages such as Spanish or Italian, Slavic languages tend to merge word-final and word-initial vowels, with no differences in airflow, intonation, or pronunciation to insert a "space" between adjoining words. Some speakers do this more than others, depending on the dialect or individual preference. Russian does this because it's stress-timed, so the unstressed vowels of a sentence aren't very important to comprehension and can thus be reduced to schwa or merged, but it's important to note that the existence of this feature doesn't actually correspond neatly to whether a language is stress-or syllable-timed. That just happens to be the reason why Russian in particular has it. Spanish merges vowels, yet it's syllable-timed. Stress-timed, Germanic Danish has a tendency to merge vowels, while German and English with those same characteristics do not.
It would be much easier for English speakers if Russian regularly used a word for 'to be' ("Я есть Грут!" &c.), rather than just a dash/pause or nothing at all! Think of это here as being 'this is' rather than just 'this' - you can then neaten up 'I - this is he/him' to 'I am he/him' without so much trouble. There are Russian words you could use, but you will sound ridiculously formal https://forum.wordreference.com/threads/using-the-verb-%D0%AF%D0%B2%D0%BB%D0%B0%D1%82%D1%8C%D1%81%D1%8F.2392865/ - much the same tone as using 'I am he' rather than 'I am him' : p.
I can't really get my mind around why here are mostly comments of whether or not "I am him" is the correct form in English and not whether or not "Я это он" is correct in Russian. You can't translate 1:1 the languages, you have to adjust the sentence a bit more. If there is ever situation that you would need to use this confirmation form in Russian, you would rather use "Я он" and leave the "это" part out.
That would be 'Это я'. The sentence given is for saying you are a particular man, or at least a masculine noun.
Maybe you and a friend are playing Monopoly and are using the dog (собака) and boot (ботинок) pieces. You could point at the boot and say "I am he/him" because the boot is masculine, but "Я это она" for the dog, which is feminine because of ending in 'a'.