وَعَلَيْكُمْ
Translation 
The Prophet (peace and blessings of Allah be upon him) said, “When the People of the Book (Jews and Christians) greet you, reply by saying:
“And upon you.”
Note: Some scholars had mentioned that this form of reply is only if you are not sure what they had greeted you with, but if the greeting is comprehensibly clear (e.g. not using words such as As-Saam instead of Ass-Salam) then one should reply the same way he would to a Muslim (this was the ruling of many prominent scholars of our time and times before) and Allah knows best.
“And upon you.”
Note: Some scholars had mentioned that this form of reply is only if you are not sure what they had greeted you with, but if the greeting is comprehensibly clear (e.g. not using words such as As-Saam instead of Ass-Salam) then one should reply the same way he would to a Muslim (this was the ruling of many prominent scholars of our time and times before) and Allah knows best.
Transliteration
wa ‛alaykum
