Walaikum Asalam Joseph/Yusuf,

Welcome to Islam! I actually know someone else to whom the exact same thing happened, same name and everything. For those who come from an Arab background, calling you by the Arabic version of your name might have just been easier for them and nothing more. Actually, it is interesting to note that the name “Yusuf”, while it has become an Arabic name, is not originally from Arabic, since Prophet Yusuf (PBUH) himself was not an Arab.

However, there are some Muslims who believe that you must change your name to an Arabic name once you convert/revert. This is simply not true. There is no evidence for this in the Quran or sunnah. 

The general principle is that you can keep your name as long as it doesn’t mean something bad. For example, someone with a name that means “ugly” or “evil” would be advised to change his or her name out of respect for the beautiful and good nature with which Allah (SWT) created all human beings.  

But having an Arabic name is not required of you as a Muslim, since you are not becoming an Arab. The Arabic language has significance in Islam because it is the language in which the Quran was revealed and has been preserved, but the Arabs or Arabic names generally, in themselves, hold no superiority to other ethnicities or names from other languages.

We are only superior by way of piety and this is equal opportunity and only for Allah alone to determine. So, if you don’t like being called “Yusuf”, and since your name means something very good (Allah Almighty increases in piety, power, and influence–the same meaning as Yusuf), you have every right to very kindly ask people to call you by the name your parents gave you.

I hope this helps. May Allah bless you in your name, which ever iteration of it you decide to go by, and make it a source of good for you in this life and the next. And please check out these links to learn more:

http://aboutislam.net/counseling/ask-about-islam/story-prophet-yusuf-wife-al-aziz/

http://aboutislam.net/counseling/ask-about-islam/need-change-names/