Answers to Questions by Yair Davidiy (7 September 2017, 16 Elul, 5777)
As Jews almost always end up marrying other Jews, does this mean in any country in the world (eg UK, US etc.) would Jews and their descendants almost always be proficient in Hebrew and their native country's language today (unlike other immigrants)?
https://www.quora.com/As-Jews-almost-always-end-up-marrying-other-Jews-does-this-mean-in-any-country-in-the-world-eg-UK-US-etc-would-Jews-and-their-descendants-almost-always-be-proficient-in-Hebrew-and-their-native-countrys-language-today-unlike-other-immigrants/answer/Yair-Davidiy
Most Jews being educated can speak the language of the country they live in reasonably well.
They also may learn English or French in school or whatever educated people are expected to have a knowledge of.
If they are religious they will acquire a basic understanding of Hebrew and perhaps also of Aramaic. These are distantly related to Arabic.
In some communities many will also gain a working understanding of Yiddish which incidentally makes German easier to understand.
Not bad for a beginning.