Have you ever heard from a native speaker “ты же …”, “ты ж ….”? If not – you will hear it with probability of 99%.
So, what really means the particle ЖЕ?
The particle ЖЕ just increases intonation and empowers the sense of a phrase.
Ты человек – you are a human
Ты же человек! – you are a human!
Мы уже закончили – we have already finished
Но мы же уже закончили! – But we have already finished!
And what about Ж? This is just a short form for the same ЖЕ that has the same sense and can be used in the same cases.
Ты человек – you are a human
Ты ж человек! – you are a human!