I recognized it immediately, and then [french horns] added a line from the same part of "Fellowship of the Ring". Gandalf had given up, everything was silent for a time, then he started laughing, realizing the translation of Narvi's words were not "Speak, friend, and enter" but "SAY 'friend' and enter". So the word he spoke was "mellon", Elvish for "friend". As a teen, I read and re-read LOTR, but often would just reread the whole part about the Mines of Moria. That stood me in good stead for the dungeons and dragons era in the 1970s. ;^)
Awesome.