YOU SAID:

I don't know who the dog is

INTO JAPANESE

私は犬が誰かわかりません

BACK INTO ENGLISH

I do not know the dog is someone

INTO JAPANESE

私は犬を知らない人です

BACK INTO ENGLISH

I am a person who does not know the dog

INTO JAPANESE

私は犬を知らない人です

BACK INTO ENGLISH

I am a person who does not know the dog