Is "We'll talk it later" as correct as "We'll talk about it later"?
It sounds correct to me because in Spanish I can say "Lo hablaremos luego" or in Italian "Ne parleremo dopo".

And what about "We'll talk it over later"?

Question

Is "We'll talk it later" as correct as "We'll talk about it later"?
It sounds correct to me because in Spanish I can say "Lo hablaremos luego" or in Italian "Ne parleremo dopo".

And what about "We'll talk it over later"?

Answer

If you don't want to say "about," you can use "discuss" instead of "talk"
discuss X=talk about X
We discussed dogs=we talked about dogs
We'll discuss it later=We'll talk about it later

OR, you could erase "it"
"We'll talk later" is a fine sentence

Answer

I think:
Hablaremos luego = We'll talk later
Lo hablaremos luego = We'll talk about it later.

It's a simple thing:  In Spanish, 'hablar' can have a direct object (lo) but 'talk' in English can't.
eg:   let's talk.   talk TO me.   talk ABOUT something, etc.

Your second question:  'talk something over' is a different meaning, like discuss the good things (pros) and bad things (cons) and make a decision together.  :)

Answer

"We'll talk it later" is incorrect.