Amina Inloes, Amina Inloes is originally from the US and has a PhD in Islamic Studies from the University of Exeter on Shi'a hadith. She is the program leader for the MA Islamic Studies program at the... Answered 2 years ago

It is not compulsory for children to learn the mother tongue of their parents.

However, given that much of the Islamic heritage is expressed in languages such as Urdu, Persian, and Arabic, from a religious perspective, I think it is tremendously helpful for them to have at least some understanding of one or more of the "heritage languages" of the Islamic world. It will help them cement their Islamic identity and feel connected to cultures and practices that are expressed in these languages, as well as have access to teachings, majalis, lectures, etc, that are not available in other languages. 

Also of course it's good for them to be able to communicate with their relatives.