Many people speak a little English, and you'll pick up some of the basic essential Thia words quite quickly. Do not worry too much about the language issue.

THB30K is not a lot, most of my Thai staff earn more than this, some more than double this (plus they have additional benefits, like monthly and annual bonuses, private and Govt medical schemes, car/transportation allowances etc...)

Sure you can rent a room for THB 5,000 per month (but it'll not be very comfortable).