"He is me."
Translation:Anh ấy là tôi.
1/ If you are referring a man with a third party, "ấy" usually cannot be omitted, just as in this example, "He is me". "He" is someone being mentioned in a conversation.
2/ On the other hand, "Anh là tôi" (without "ấy") implies that the man (Anh) is directly involved in the conversation between you and him. In other words, "Anh" here not only serves as a second person pronoun but also helps to specify the gender (male) of the subject.
If you only use "Anh" then it implies that you are talking DIRECTLY to a male/man. "Anh là tôi" means "you are me." When you use "ấy" then it means "other/the other guy/HE" so it's implying that you are referring to someone else. "Anh là tôi" = "you are me" and "Anh ấy là tôi" = "he (the other guy) is me."
I love questions like this, and they are the hardest to answer. They really test my Vietnamese knowledge.
Both đó and ấy mean "that" or "there." They are interchangeable, but I believe đó is used to refer to someone who is not in viewed. There is a little notion of the unknown, somewhat distant, less certain, and less specific than ấy. So "Anh đó là tôi" should work here since obviously "he" is not there.
I'd have to respectfully disagree with the comment from TuPham844495 as Vietnamese does have SOME gender based grammars. To answer your question, "toi" and "ban" are both neutral gender words. "Toi" = "me/I am" and "ban" = "friend." Examples of GENDER based words are "anh" which is masculine and higher in hierarchy, and means "brother (literal)" and/or a man/male that has a higher hierarchy. "Chị" is feminine and higher in hierarchy, and means "sister (literal)" and/or a woman/female that has a higher hierarchy.