"I don't know why I'm seeing so many punctuation issues surrounding dialogue," he said, utilizing a dialogue tag with the correct punctuation and formatting.
"What do you mean?" She stood up, starting a new action after her line of dialogue.
"I'm talking about this--" he interrupted himself but continued the same sentence after a brief narrative description, "--this weird capitalization, like people don't recognize that dialogue tags like 'he said' or 'she muttered' are still part of the same sentence as the dialogue. The tag and the spoken sentence should be separated by a comma, not a period."
She looked at him thoughtfully as an action separate from her dialogue. "You mean that, unless I am starting a new sentence or action following a line of dialogue, I should treat my dialogue tag as part of the same sentence?"
"Yes!" he exclaimed, still in lowercase as part of the same sentence even though a punctuation mark other than a comma was used. "You should only capitalize the word after your end quotation mark if you intend to start a new sentence after your line of dialogue."
"So then I shouldn't punctuate my question like this?" She asked, capitalizing unnecessarily in the middle of a question.
"No, capitalizing in the middle of a sentence is generally considered wrong," He assured her, doing the same thing but after a statement.
"I think people are running into trouble because phone keyboards automatically capitalize the next word after a period, regardless of whether or not it is following an end quotation mark," she observed, correctly capitalizing again after her demonstration.
"That's great and all," he said, putting his dialogue tag in the middle of a sentence to demonstrate how to capitalize dialogue upon narrative interruption, "but people need to learn how to use punctuation correctly and not just rely on autocorrect."
"That's true." She sighed, but separately from her dialogue. "This post is getting a bit long in the tooth isn't it? We should wrap this up."
He agreed, vigorously, before his dialogue but still as part of the same sentence, "Oh my God, yes, let's."