Considering there is no one single Chinese language, it’s an interesting thought experiment to wonder what would happen if a microcosm of China went to live in isolation somewhere-- on another planet, or wherever.
According to a Taiwanese friend of mine, pretty much everyone in China studies Mandarin in school, so I’m guessing that in the microcosm, the non-native Mandarin speakers would be using what Mandarin they knew as a lingua franca, but I’m still pretty sure that for various reasons words from other dialects would end up in whatever language developed, and that the influence of all the non-native speakers would alter the pronunciation of this para-Mandarin significantly.
Add a group of American English speakers to the mix, and two facts of language assimilation: one, that more Chinese people will have studied English than Americans will have studied Mandarin; and two, that Americans are extremely facile in assimilating loan words, my prediction would be that after about three generations, when you have a new language, and no longer a pidgin or creole, the grammar will be more English-like, albeit, with lots of irregular forms lost, and lots of English vocabulary will have survived for anything that was more prominent or popular among the first generation of Americans; however, any time Mandarin and English vocabulary items were in competition, and pretty much evenly matched, the Mandarin word would tend to win out.
I would also predict that Roman orthography would win out, but some simplified Chinese characters might survive as abbreviations, much like the ampersand; there would just be a lot more of them.
One unknown variable I can’t guess at is prestige. In situations where pidgins and creoles develop, and eventually emerge as a new language (ie, Middle English from Old English and Norman French), sometimes one language is considered more prestigious than the other, so the people speaking the original pidgin make an effort to use one language over the other.
I’m not just making crap up, FWIW. My mother had a PhD in linguistics, and books full of stories of real situations where things like this happened.
/hijack