I don't think so. Like sure, if you're a Bangladeshi living in Tower Hamlets you could probably get away with a limited life speaking only Bengali, but you could say the same about Spanish in swathes of the US. Realistically, you need English.
I was surprised the first time I got into volunteer work. Figured that these wives have never spoken English in their home country. So when they moved to London, they learnt English from scratch and picked up the local accent and speaking style. Their grammar may not be perfect sometimes but whose is?