dialects and accents

Ahoy, fair readers! Since today be International Talk Like a Pirate Day, I'll be talkin' like a pirate for t' rest o' this post.

Because o' International Talk Like a Pirate Day, now be t' time t' discuss DIALECTS and ACCENTS!
How a character speaks be rather important. It reflects where they be from and how they were raised - I don't have t' same accent as me cousins, even though we be blood relatives; it be because I grew up farther north in t' US than they did.
Now, ye may be thinkin', why is Knitter talkin' of talkin'?  What be so important about t' way t' characters be speakin'?  T' importance be two ways:
First, the character be havin' a back-story.  T' manner of speakin' reflects that.  It makes yer characters more real, if ye know how ter write the dialect right.  Jus' be wary o' overdoin' the dialect an' gettin' too far inter it, because then nobody will understand it, except ye.
Secondly, yer character's dialect can be a plot point.  If Pakpla's long-lost cousin cannot understand what she be sayin', thar can be a drastic misinterpretation and t' Grand, Villain-Defeatin' Plan can go horribly awry because Pakpla's cousin does not know what he should be doin'. Also, Pakpla's long-lost cousin, due t' their different dialects, might not even realize that they are related, even if Pakpla has been lookin' for her cousin for t' last twelve years.

Since dialects be important for tellin' where a character be from, you could use them for character tension. There could be stigma between Pakpla and Habroje because Pakpla's accent says she be from t' West, and Habroje's says he be from t' east, and EVERYONE KNOWS that Easterners and Westerners hate each other. (not really. I made that up). People make assumptions based on how someone speaks, and an accent or a dialect be a way for someone t' pass judgement on someone else. I do not condone judgin', but if it makes for a good plot point, I may have me characters judge each other.