I was thinking maybe we had Robinson Crusoe wanting to "civilize" Friday?
It's an interesting question...there are folks using "Ebonics" who
seldom encounter standard English in daily routine...
It's the OP's English one wonders after. Where I'm from, I get hung by the
toenails and throttled, if I use the word Negro, usually with threats that
I'll be shipped off to a redneck rehabilitation camp. (Same with the word
Oriental, when referencing people. And, annoyingly, the word Mexican, when
referring to those living in US.)
...as much as I'd like to say there is a 'software', I think the 'program'
I'd recommend is the evening news on TV....that is usually the best guide
to a neutral use of the language.
There was that movie, Melanie Griffith, named Working Girl. I disliked
the movie, but what comes to mind is how she listened to tapes of someone
from a higher socio/economic class, and then repeated after those, to
change her enunciation style. The suggestion about the TV sounds good...
yet it might not do the job, in itself. Really, it seems a pretty hard
subject -- how to change your accent once you're already an adult. (I'd
once spent several years trying to incorporate a good drawl into my speech,
and made only small progress.)
What does seem likely is that it's a subject beyond software recommendation.
Some of the inhabitants of alt.usage.english might be best qualified to
answer. Although there again, it is the English usage of the OP which could
give rise to question.