Mumbai is a 24x7 city.
There are Rich people & not so Rich staying here.
English is well understood too by most.
If you want good Accomodation I'd say Bandra West approx 7-8 km from the Airport.
Its not a toilet as some folks suggest.You need to be here to Judge.
I work at the Airport & live at Bandra west.I travel to work in 7 mins at night & 20 mins in the Day.
regds
MEL