Ben

When and why did Obi-Wan become Ben? After he gives Luke to Owen, I presumed he just made a hut and stayed there. When and why did he become Ben?

My theory on this is because he needed to let Luke know he wasn't a Jedi. Any other suggestions?

 

That sounds like a good theory. I can't think of anything else. Ben maybe came from Obi-Wan, the -bi part and then the -n in Wan. But he wouldn't call himself Bin Kanobi, so he changed to Ben Kanobi...

 

That's a good question.. I think I agree with Saora_Bin

 

The line about "not being called that since before you were born" is a plot hole than, or mistake by Kenobi?

 

It's a generalization. He doesn't mean that the second Luke was born, he ceased to be Obi-Wan.

He was generally known as Obi-Wan in the years leading up to the birth of the twins.

He was generally known as Ben in the years following the birth of the twins.

 

I just assumed he changed his name to Ben just to make sure there was no connection between him and Luke Skywalker. Even though they were in the Outer Rim, I think he still wanted to keep a low profile even if Vader wasn't looking for them.

I agree about the "Oh, since before you born". Basically it's true, as soon as the birth happened they went into action with the twins...so I can see him saying that.