Your points make sense and I agree with you mostly. But I still believe that, although "silent protagonists" are a kind of protagonists in video games, there's more behind Chell's silence. There's more behind Chell in general.
Shoot two Portals in a corner and have a look at her. Does that look...
I have mice and one day I "lost" one. I put cheese and breadcrumbs on a plate and once it was there eating them I just took it and put it back in its cage. Easy.
I'm from europe and I just know that on those shows they have on mtv people always have weird names. I'm not talking about the weird nicknames like "New York" but about real names of actual people who their mothers named "Destiny" and "Jewel" and stuff like that. I find it ridiculous.
No, a textwall looks like this:
See? It's not the same.
On another note: I also forgot to mention that I don't believe the Gman is linked to Aperture Science or only linked to them in the same extent he was linked to Black Mesa. He's far superior. The way he speaks sounds like he had to learn...
There's a man and a giraffe sitting in a pub. They get into a fight and the man beats up the giraffe. When he's about to leave and the barman says "you can't leave that lying there" and the man says "it's not a lion, it's a giraffe".