Ernest, I can see possible issues with the example you mentioned, about moving back and forth between characters and then having multiple paragraphs of dialogue from a single character. Yet most readers will see the closing quotation mark or the lack of it. I’m certain you’d end up creating more problems if you were to have a closing quotation mark in one paragraph and an opening quotation mark in the next paragraph if the two paragraphs contain the words of a single speaker. That is, the instances when a reader doesn’t note the absence of a closing quotation mark will be fewer than the instances when readers do note the presence of a closing quotation mark where it’s not supposed to be.
When a dialogue speaker is using scientific or foreign language terms in the flow of his/her English speech, should these be italicized? . Homo sapiens or je ne sais quoi or bundibugyu ebolavirus --that is, should terms or words that would normally be italicized when incorporated into the narrative section of writing be italicized within quoted sections of dialogue? I ask because I only recently realized the reason we are taught to write out numbers as words in direct speech is because people don't/can't say numerals, so I wondered if the same were true for italicized words from science and laungauge.