Think about it - when you’re having a heated discussion with someone – you stop at a point and say something like, “I realize you didn’t say I have two left feet when I dance and I even look ridiculous, but your voice – the way you said and your expression implied it.”
How your characters speaks, his/her diction, shares a lot with your reader. You inflict voice when your characters speak. It’s not only diction, attitude, POV, and dialog but it’s also speech, thoughts, and descriptions. This is what we call our character’s voice.
Accents whether national or regional give a character a distinct voice. Consider the timeframe you’re writing and realize you can add flavor to your story with your character’s voice. Be careful not to add too much dialect or accent. A reader shouldn’t stumble over dialog. This is a situation where less is more.
“I’m beholden to ya, mister. She’s a mighty fine lookin’ filly.”
That works to some degree, just make sure every line isn’t loaded with heavy dialect or accent.
One last thing is be sure to know your dialect or accents. Readers are extremely critical when it’s incorrect or difficult to translate. If done with a fine hand, dialog enriches your character’s voice and brings your story alive - making your characters believable.