In The [Lord of the Rings: The Two Towers][1], at `Helm's Deep` when `Eragon` was commanding the Elves in Elvish language during the battle, he yell's -

>"Ladders"

A moment after that we hear `Gimli` saying -  

>"Good"

because he was very eager to fight them and finally the wait was over.

But how did he know what `Eragon` said? How did he know Elvish?


  [1]: http://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&sqi=2&ved=0CB8QFjAA&url=http%3A%2F%2Fwww.imdb.com%2Ftitle%2Ftt0167261%2F&ei=r0mCUPm_PMrprQeR4oHwAQ&usg=AFQjCNEYlGUMiSBZP_E4tO_WLELqKB8UBw