Can I speak French in Vietnam?

I want to go to Vietnam but I don't speak vietnamese, but I speak French, where can I find the are with a lot of french speakers?
As an American is it dangerous to be in a communist country?
Do they sell any Pho and com dia??
Thanks.
the whole point is to visit vietnam and speak French because it's part of the francophone group

During the first Russian Roulette scene (going to try to give nothing away) one man has a gun to his head and a soldier keeps striking him and yelling "MAO!"* repeatedly. Any Vietnamese/French speakers know what this means? (I say French as well, because it's widely spoken over there due to the French occupation of the country before the war.)

* "MAO" is pronounced just like it's spelled...as in Mao Zedong.
Bueller...?