The Naeldor Campaign will make use of the DMFI tools. The DMFI tools add features like languages, emotes, and player messaging to the interface. For example, if your intelligence is high enough, when you log in for the first time with your character, you will get to select extra languages that your character speaks. You will then be able to use the interface to speak that language, and only other characters that understand the language will be able to understand and converse with you when you speak that language. Instructions on downloading and installing DMFI can be found here, just below the WorldGate link. As far as I can tell, installing DMFI has no adverse effect on your game when playing non-DMFI modules. I had it installed on Sunday when we played through the official campaign, and the only difference was that one of my right-click context menus had a DMFI option on it that didn't do anything, since DMFI is not installed on the official campaign.