Indicativo imperfecto a la Dominicana

In DR, many people change the 'm' for a 'n', when speaking, like in the plural first person of the imperfect for example:

Jugabanos instead of Jugabamos
Comianos instead of Comiamos
Mirabanos instead of Mirabamos

You can also notice this when there is a 'm' before a 'p' or 'b'.

for example

bombero we say bonbero
campo we say canpo
pompa we say ponpa

although we know the way it is written, we just seem not able to pronounce the 'm' in these circumstances.