"Like this. In fragments, I mean," she replied.
"Don't people go, um, ah, er a lot? And interrupt each other?"
"In real life, yes. In stories that doesn't work so well."
"So in stories, people don't talk like they do in real life?" he said.
"No. Dialogue in stories always has to move the story, show character, elaborate on a theme, or have some other definite purpose."
"Anything in particular to avoid?" he expostulated.
"Yup. Avoid what we're doing now," she interjected. "Said-bookism always rings false. Just use 'he said' or 'she said', or 'replied', or 'asked' for most dialogue tags. And a lot of the time you don't even need those."
"And what about adverbs?" he asked inquisitorially.
"Whether you're writing dialogue or not, adverbs almost always blow goats," she said assertively.
"What about dialects?"
"Whut, aer yew arsking if'n it's okay tae mak' wi'th'silly spellings fer accents 'n' sich?"
"Hmm. Sounds like the answer is no," he said.
"Not unless you're really good, and even then, it needs quite a light touch."
"Okay, thanks!" he said, and walked away.