Most of this video is a lot of Alduin's yammering about how awesome he is, but around six minutes in, he starts on some really interesting lines:

"Alduin's power grows. You must stretch your neck to him."

"All creatures know Alduin is my master."

"I come in peace."

"Good."

"Beware Alduin's fire!"

"Then speak."

These lines appear to have been meant for dragons other than Alduin. Considering their generic feel and the fact that I couldn't find them anywhere in the dialogue files, I'm guessing that they were written as test lines so Bethesda could see if the actors' voices were dragony enough. That would explain why Daniel Riordan is reading non-Alduin dialogue -- he wouldn't have been cast yet.

I noticed that the lines suggest a less aggressive personality than what ended up being the norm in the game. However, if these are indeed test lines, the writers may not have been worrying about that, or maybe the game wasn't developed enough for them to know that it's highly unusual for a dragon to "come in peace." 

There's also a potential new phrase here: to "stretch one's neck" appears to mean offering one's allegience or bowing down to betters.

Just thought it was interesting and wanted to share. :)

Cool finds! I swear I've seen the "stretch your neck" phrase before.

I found them all on a realmofdarkness soundboard. (Can't link to it because of my stupid internet :D) It said that the dialogue was supplied by ICEnJAM (look it up on YouTube). I wonder how people get their hands on this stuff if it's not in the dialogue files O.o

Hmm... I should probably mention that I don't have the PC version, so I didn't delve into the actual game files. I searched the unformatted dialogue file found in the Library, so it's possible that these sounds can actually be found encrypted in the game. Other than the game files, I have absolutely no idea where these people get this stuff. But when I get the chance I'll definitely check out that website! Thanks for the input.