"I am not a book."
Translation:저는 책이 아닙니다.
I think we use 는 and 은 as the topic particle. To make a plural topic, then we should use (in some cases), the plural particle 들 + 은. Also, I think that the pluralization would not be always necessary.
남자들은 (Men) 아이들이 (children) 아닙니다 (are not). This would be a possible translation for: Men are not children, I am not too sure (as a general sentence, the pluralization would not be necessary in Korean), and I still think that Korean people use some different forms to translate the English sentence.
Also, I am not really sure if the plural particle is necessary if we put the plural pronoun, then 우리는 (We) 아이들이 (children) 아닙니다 (are not).
I hope it helps. =)
EDIT: I have put the incorrect marker, the correct is called topic used to add emphasis, contrast, or to limit what is being talked about. Now it is fixed, and I add the reference from the Notes - To Be (by Soedori)
| Limited topic | 저는 여자입니다. (I am a woman.) | Irrelevant of anyone else, I am a woman. (May imply that someone else might be as well.) |
| Contrasting topic | 저는 여자입니다. (I am a woman.) | Unlike the others, I am a woman. |
은/는 can be used with general statements as well because you only want to talk about the notion as a group, and nothing else.
Korean Notes Repository (===under construction==): https://www.duolingo.com/comment/24352980
는 and 은 are suffixes that mark the subject of a sentence. 들 is the plural you're thinking of. Also, "we/us" has its own word - 오리. 오리는 = we, 오리를 = us.
im not good in korean but "저는" is like a formal way for first person. i always hear celebrities say "저는" when they are talking to a crowd to sound "formal" and appropriate to any ages
If 이/가 are subject markers why are they used in this context when a book should be an indirect object here? I dont think theres such thing in english but in my native language the book would be an object here, so shouldn't we use different markers instead or 이/가?