With the power of the internet, you can find lots of dead languages (or ones that aren't quite dead) online to use for your languages.
For my Marth setting, I combined lots of Native American words, with name generation websites, and then I threw my own made up words in the mix.
For me, it helped to have a list of words to use while naming things such as rivers, kingdoms, towns, cities, races, etc.
When you choose a language that was once spoken, it generally has a similar sound to it, so it sounds more real (well, it actually was real so that helps, hehe).
http://www.wordgumbo.com/index.htm
I used that site a lot while making up stuff for my world building project.
Enjoy.