In writing we use these quotation marks to show direct speech.

In the record the speeches are given in direct speech.

They're communicating with each other by direct speech through the helmet contact.

I'll have to take a course in direct American speech sometime.

Quotation marks are also used in some other cases besides direct speech, for example around the name of a song.

I cried, and my voice came out as direct speech, intimate, just between us.

For all of her direct speech, the woman still didn't really explain things.

The vocative case, which is used to address someone or something in direct speech.

So far as I recollect neither of them made any answer to this direct speech.

They first began to quote direct speech in 1714.