So you want to invent a cool alien race, complete with a fleshed-out language, for your game, book, movie, or personal benefit. There are others like you out there: they're called conlangers, and they construct elaborate languages for fun or to make the portrait of an alien race more believable. Rule number one of conlanging, however, is know the history of human languages. That way, you know the range of what's already been done — and you can deviate from it accordingly. And this beautiful chart of the history of Indo-European languages is just the thing to get your brain zooming.
Conlangers include everyone from Marc Okrand, the linguist who wrote Klingon, to the nerds who invented the most perfectly logical language in the world, known as Lojban. Anthony Burgess invented a little conlang for his characters in Clockwork Orange, and Suzette Haden Elgin's Native Tongue trilogy is all about a group of rebel women linguists who create their own language to subvert their ultra-sexist society. Sometimes Hollywood employs conlangers to make alien talk seem more realistic, and sometimes conlangers wind up going into computer programming, where they can invent computer languages to their heart's content. Larry Wall, inventor of scripting language Perl, is a conlanger, for example. And nobody who has ever used Perl will be surprised to hear that. Chart via Bartleby.