Hartley: Most (really) Dominicans cannot distinguish bs and vs...
In "theory" the v is slightly "fricative" which means that there is a little brush of the lips.
The b is supposed to be slightly "explosive" ....
However, reality indicates that you can get away with pretty much everything.
Me boy = me voy ben = ven...and so forth.
This is not a really important matter. What matters more are your el and la; los and las
that is what really screws up a non-Spanish speaker....: La problema, la mapa (NOOO!!!) El problema, el mapa *YESSS*....
Rule of Thumb: if it ends in -ma, -pa, or -te, its masculine and therefore "el"....
Don't sweat the accent, you cannot lose it, but you can make yourself understood, and that is what matters.
QUERER CERBAISA will get you the same cold President as Quiero una cerveza.....
Good Luck!
HB