I know how to speak Boston:
1) Words like Car are pronounced "Caaaah".
2) Words like Cast are pronounced "Carst"
3) The word pronounced "Khakis" means Car Keys.
4) The words pronounced "Car Keys" mean a certain type of light cotton pants usually tan in color. You can put your khakis in the pocket of your carkeys.
5) If you want a soda pop, ask for a tonic.
6) And the biggest mistake people make that make them stick out like sore thumb: Pronouncing Boston like it has the long A as in Baaaston. O's are pronounced more or less normally. Perhaps a bit of "Bawston", but never anything dramatic.
That's about all I know
Thanks for the tips:-) I imagine instead of BAHSton, we'll be saying BAWWSTUNN, and that will also make us stick out.