Anyone know?

Ok, someone needs to tell me if I’m going insane.

English was one of two subjects I got A’s in at school. After school, I went to college and did my A-levels (the equivalent of an American Associate’s degree) and got an A in English there as well. Finally I went on to University and got my Bachelor’s degree in English Language and Literature with a minor in writing studies.

As such, you’d expect me to know my way around the written word, right?

Then, last night, I read an article and found the way I write dialogue is supposedly completely wrong. I’m trying to work out if I’ve been taught by a parade of incompetent teachers, if this is a stylistic thing or if it’s an American English Vs. British English thing.

The way I was taught to write dialogue is that, for basic grammar, you essentially ignore the quotation marks, for example:

“If the spoken sentence ends with a period, the next word should start with a capital letter.” Said the Teacher.

Or:

“If the spoken sentence is broken by a comma,” said the Teacher, “you don’t capitalize.”

Then, today, I was reading an article on grammar and discovered the so-called ‘sentence extensions’ should never be capitalized unless it begins with a proper noun. For example:

“Even though there’s a period at the end of the quoted sentence, you shouldn’t capitalize the extension.” said the teacher.

“Of course, if a proper noun is at the start of the extension, you should still capitalize it.” Bob said.

To be honest, I think both ways make sense…but I can’t work out if this is a stylistic thing, and American English Vs. British English thing…or if all my English teachers have taught me the wrong way to write dialogue.

Is there anyone ‘in the know’ that can set me straight? I’m even more confused after writing this because when I tried to type in the supposed ‘correct’ way (not capitalizing the sentence extension), Microsoft word auto-correct kicked in and capitalized it for me.