buy good earplugs - their language is BRUTAL on the ears.. My good bros wifey is Viet... She speaks TOTALLY normal english but when she's talking to her Mom, you need those airport earmuff things..
BONG BONG BONG BONG BONG BONG.... They talk loud too!!
My Bro went for a month with her whole family last year. He said it was a great trip.. They did all the touristy ****, he had a blast.