Dialogue is always punctuated within double quotes. "........."
Quotes are always punctuated within single quotes. 'To Be Or Not To Be'
Never use italics to denote quoted speech (why? because it's impossible in handwritten articles).
Quoted speech within a dialogue is therefore:- "Jack said 'Are you still going?' "
This is the standard ENGLISH punctuation that I was taught 70 years ago in Worcester, England, and I see no reason to alter from this standard.
Yes, we all know that some in the modern generations have this thing, like dogs, of making their mark on the lamp-post and changing perfectly good rules. However, all this does is to achieve confusion where there was none.
[Another example of lamp-post marking was the British Meterological Office who, wanting to make their mark on the lamp-post decided that they would give new dates for the start of the seasons. This was total nonsense and absurd, and purely to help inflate somebody's tiny ego in the Met. Office. The same people did exactly the same with changing from Fahrenheit to Centigrade under no imperative from the Government, when everyone knew that Fahrenheit was a far better graduation system.]