How would one get a language to evolve in a laboratory setting?

Assuming one has the money and facilities to conduct such an experiment without disturbing a whole region or city, I guess how would you get it to happen? Important things to consider would be how you would you get a stable population that would last long enough for a language to evolve and how would you instill in them a common language to begin with that isn't just English or the dominant language of the country you're in.