There is no need for any certfication to be a voice n accent trainer.
If u have strong grammer concepts, n know how to present urself in a comprehendable manner,,,,u r all set to go.
the first n foremost is u shud know how to pronounce words properly.If we miss out on pronounciation, the fun of commnicationis gone.eg.
if a person living in rural area says sakool to school….the other person wud surely give a bad face to it.
We shud also have medim rate of speech.Generally its accepted between 110-140 wpm.If we speak crisp n clear, even if we speak
I think soft skills are all about how u deal wid people n present urself.Proactive listening is utmost imp.if we dun understand wat the other person is saying…then the commmuncation is void.we have to have empathy in our daily life as well.Empathy is understanding the issue n present an alternative.