Are you sure bob? I spent some time just now and it seems he says the normal things at first, but then his voice changes (not as gruff) and he said an awful lot of stuff which he never repeated untill his voice became gruff again, at which point he said the things they all say, but never the stuff he said in his "clean" voice.
Some of what he said seemed to really mess up the story D:
He seems to indicate that the vortigaunt are of one mind, they all know everything each one knows (i seem to recall this being stated elsewhere in the game by a human).
He says that no veil of time or space can blind them. (something like that)
Also he says they clearly see you in black mesa, and in the nihilanth's chamber. o_O
I may just have to go download gcfscape and listen to these things over and over outside the game and make a full text file of them >_>