I've moved around a lot for work and as a result have lost a lot of the dialect that I grew up with. I try not to use the slang words that are common from my area because people don't understand what they mean.
While this may be old-fashioned, I do think if you want to get on in a professional environment it's best to speak relatively correct English. I'm not talking about accent here - I think that is something different.
I try and get my DC to pronounce their words properly and speak well. I don't think there is any harm in them knowing the slang / dialect words where we live at the moment but I don't want them using these routinely.
Sadly I do think that people still judge other people's ability / intellect by the words they use. AIBU?