In my not-too-far-future world, under a treaty from the U.N., participants from several nations (less than 10,000 total, from mainly France, the U.K., the U.S.A., alongside minor contributions from other countries) will travel by spaceship to a very far distant planet, taking maybe thousands of years to travel. When they arrive, they will use the built-in Terraforming unit to transform the terrain and vegetation to better match earth biomes.
The reasons for this are to increase trust and unity between the nations participating, to explore different environments and planets, and to develop better technology as a result of the mission.
Naturally, the organization coordinating the entire mission has developed an international language (think Esperanto) with phonemes that are most common within the languages of the people selected and are easiest to pronounce, no complicated orthography (selected characters from the Latin alphabet with one accent mark), simple grammar structures that are easy to learn and use, limited verb tenses (only past, present, future, interrogative, maybe a few others depending on necessity, but no preterit vs. imperfect like in Spanish), etc.
Everyone participating in this mass migration will have to learn the language and be willing to speak it as a main language.
My question breaks down into 3 categories:
- Is the creation of this international language realistic as opposed to maintaining the original languages? (obviously, communication and unity would be increased, so I'm thinking most likely yes)
- Will the people on the spaceship revert back to speaking amongst their own groups with their original language, or will they speak the unified language? (the organization will encourage usage of the language but never enforce it)
- (possibly a duplicate of 2) Will this result in there existing several main dialects which eventually break apart into pidgins and eventually break into their own rehashed versions of the original languages?
Thanks in advance! Comment/edit if it needs more explanation or clarity.