Hallo. ^.^ I've been thinking about one particular story lately, my Master Creation, which is still in the works. (well...Master Creation on the standards of me. Which may not be so masterful to the rest of the world when all is said in done. But it is a rather monstrous project.

) This story deals with several different countries and several different cultures over the span of many different years, stretching over several books worth. The overarching plot itself
revolves around these different countries and cultures, their histories, etc.
That being said, it would be quite unrealistic of me to have every culture throughout all time and space to all speak the same. Exact. Language.
So I've finally decided to hunker down and make up a few. Not full fledged ones, just partially developed languages, as I probably won't need a fully developed language. Just enough for foreigners to speak it, make a up a few phrases, a poem or riddle or two, add a plot twist - that sort of thing.
I've no idea where to start. Absolutely no idea. I've never invented a language before, so I need your help!
How do you invent your languages? What are the steps you go through? If you have any advice at all, I'll take it.
Thank ye kindly in advance. I apologize if the above post has any typos, it's hard to type properly when one is using a tiny netbook keyboard and one has a cat curled up and sleeping upon one's lap. >.O