Thanks ever so, milady, but me mum would hit me upside the head if I took another one. In the first example, you can see the fluttery old lady in the too-young dress. In the second, you see the overpowering harridan. In the third, you see a young, undereducated girl who may have a title but little gentility. The choice of words and the cadence of speech make a big difference in the effect of your dialogue.
Dialogue also reveals what relationship the character has with others.
Note how each line below gives you a different feeling about the relationship between the character speaking and Harry. Good to see you again. C. Advancing the Plot Dialogue helps make the story more readable and gives dimension to your story. You have to use every line of it. Plan your scenes so that the dialogue actually moves the plot along.