First of all, the Swiss pride themselves on having invented "multiculturalism" (presuming you can tell the difference between the three major language groups).
Secondly, there are millions of Americans who are eligible to be Swiss citizens simply because an ancestor was Swiss. Just show up at the correct Canton at the right time (usually on or near your 18th birthday) and make your declaration.
We could overrun the place if we wished ~ and that's just me and my cousins, and not a one of them speaks French!
The Swiss are still rather local in their loyalties, however. Their "multiculturalism" is definitely NOT the salad bowl approach we see now in the United States, but more like a main course with several items: the French mingle mainly with the French, the Germans with the Germans, the Italians with the Italians, the Romansch with the Romansch.
It should also be pointed out that the four afforementioned cultures are fairly microdiacritic. Asian, Muslim, African, etc. immigrants are definitely macrodiactitic to the native Swiss population.