2. Languages mixed in complex cultural processes, like pidgin and creole languages
3. Scientifically mixed for speaking like esperanto, ido (home), interlingua (home) and lojban
4.The more of an artwork like languages. You must go to the language construction kit!!! A known example in this direction is klingon.
5. Scientifically mixed for other purposes like utl, or TextPro universal translation languages.
6."Concept based"
Following an example for one of the many possible concepts (like in concept art). This one, with a special setting, even might be worth to be a long time research project (not for the result, but for the process):
"All speakers can use all words and grammars, as long as the other understands the message. Try intensely in a concentrated group of motivated people who speak different languages."
7. Languages of animals
Fancy old hats confusing zoo of superficial trash on the web. A bit like general pages about dinosaurs or about cats or dogs. From the messages of the bees and the pheromones of the ants, over the whale songs and the dolphin communication with Phoenix und Akekamai, to Alex the talking parrot, who really means what he says.
For a simple introduction into interspecies communication have a look in languages and apes and chimp signing behaviour with american sign language. A sign system with lexigrams, used in the communication with Bonobos, is Yerkish, see lana at her keyboard, and the keyboards of panbanisha and panzee. Finally old stories for the primates heart, Linguistic Superabundance and Naming Nyota.
8. I leave out here a lot of too attractive ones: Computer languages, body languages, secret languages ...

Also no Chomsky or linguist discussions. When this site gets more interactive, it might go more roman/german/slavic pidgin. In the interest of general readability i go on imitating english here for a while. Additional links: Machine Translation

Toys
1. Multilingual free web translators
Overview: Mezzofanti
Other free translators:
WorldLingo, very flexible free translator, hard to find on their website, sometimes out of service. Babelfish.

2. Multilingual speech synthesizer webservice
Sayso

3. Neuro-mechanic throats:
Enjoy the movies of Hideyuki Sawadas year 2002 state of the art neuralnet-mechanic-throat in action. Next level shall be the implementation of a tongue.

If you can, wait the long time for the download. If you are obsessed, the movies can be blown up to 320x240 with a little bit of fuss.

I suppose, first realised Spaceship-Enterprise-style androids will have speakers built in, instead of neuro-mechanic throats. Throats based on the research of Sawada at Kagawa University would technically be much more complex and costly.

Whether it ever will be useful for robots, or even for people whose larynx is out of function (etc.), is speculatory. The spinoff might be enough already in the field of triggering complex processes with neuronal nets.

Me as an obsessive machine celibataire,i am moved more of the charme of robotic imperfection, documented in the movie. It is sort of a "humanistic" value.