If someone tell me that he's back home ("I'm back home now") does it mean that he's coming back home now or it means that he's already at home after some time that he wasn't there?
‘I’m back home now’ means they are already at home.
It can mean that they just arrived back into their house from a short trip to the supermarket, or it could mean that they arrived back in their country after a trip abroad. In both cases, it means that they already arrived.
However, it can mean, literally in their home (supermarket example) or just ‘somewhere in the country’ like - they could be in the airport (in the trip abroad example). They are ‘back home’ meaning - back home in their own country. The exact meaning of where ‘home’ refers to (literally in their home, or in their ‘home country’) depends on the context of what is being said.
‘I’m coming back home’ means they are on the way, and not home yet.
Examples - already in home:
- I’m back!
- I’m back home now!
- I’m home!
Examples - on the way back, not yet home:
- I’m coming back home
- I’m on the way back home
- I’m on the way back
- I’m coming back now