m. c. de marco: To invent new life and new civilizations...

The Language Construction Kit will help you get started conlanging:

This set of webpages (what’s a set of webpages? a webchapter?) is intended for anyone who wants to create artificial languages—for a fantasy or an alien world, as a hobby, as an interlanguage. It presents linguistically sound methods for creating naturalistic languages—which can be reversed to create non-naturalistic languages. It suggests further reading for those who want to know more, and shortcuts for those who want to know less. —Mark Rosenfelder