In the restaurant scene, Sollozzo says to Michael:"Eo ho aiutato a famiglia Tattalia." ("I have helped the Tattaglia family.")
What does he mean? How did help them?

My guess would be setting them up in the drug business.

I'm not sure that's the correct translation. I think he's saying that he has the support of or help from the Tattaglias.

Yes, that's what he told Tom earlier. Anyway, why would he bring up his help for the Tattaglias to Michael? At that point Michael was a civilian. For Sollozzo, Michael's only purpose at that meeting was as a prop for Sol to buy more time to figure out a way to kill Vito. He'd have no interest in explaining his relationships with the other families--he'd already done that with Tom, for whom such info would be persuasive with Sonny.

My interpretation is that The Turk has the muscle of the Tattaglia Family to back him up, so therefore, why are the Corleones holding back-- "cold feet?"

Just my thought.

The turk is very disingenuous throughout his meeting with Michael. While he claims to be the "hunted one" who "mised his chance" and who only wants a truce, is is also bragging about his connections with the Tattaglias, he bad mouths Sonny to Michael, saying he hopes Michael doesnt have a temper like his brother, and he insults Vito by telling Michael that his thinking is old fashioned. This is not negotiation for peace, it is a statement that he intends to move ahead with his plane.

I'll have to read the transcript. Is that line in Italian in the transcript? So far, I don't think it's being translated correctly.