I think English knowledge is a generational thing, irrelevant of background. People who migrated earlier had to learn the local language, because English knowledge was not prevalent back then. Their kids are just like all the others, and speak English because it's a must in a globalized world.
I think that a major issue for people who are not fluent in the local language is that it's always an effort for the group to switch to a foreign language. People's English skills differ, and some of them might have it harder to articulate themselves. I personally think that the burden is on you to learn the language and not on them to learn English - as a guest, you should honor the house rules, just like you are expected to respect local laws and customs. If you plan to stay, learning to speak the language is a must. I've seen many fellow expats try to skip this hurdle though, taking classes to reach some minimum required level (here it's B1 if you want to attain a German citizenship) and then going back to expecting everyone to accommodate for them. Some people I know have been living here for close to a decade and they still struggle to order food.
I think that a major issue for people who are not fluent in the local language is that it's always an effort for the group to switch to a foreign language. People's English skills differ, and some of them might have it harder to articulate themselves. I personally think that the burden is on you to learn the language and not on them to learn English - as a guest, you should honor the house rules, just like you are expected to respect local laws and customs. If you plan to stay, learning to speak the language is a must. I've seen many fellow expats try to skip this hurdle though, taking classes to reach some minimum required level (here it's B1 if you want to attain a German citizenship) and then going back to expecting everyone to accommodate for them. Some people I know have been living here for close to a decade and they still struggle to order food.