The Language Construction Kit

"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"

Explore the kit here: http://zompist.com/kit.html