Traditional female wear????

[Dale Seago]

Not a myth so much as a lack of understanding about clothing of the age.
Shirts had much longer tails (almost like a modern nightshirt) and frequently did duty both as your base layer on top AND bottom.

Right. By the 1700s at least, the shirt was considered "underwear" and it was considered improper for ANY of it to even be visible out of doors unless, for example, you "stripped down" and took off your jacket, waistcoat, and neck stock to engage in some physical work on your farm.

I recall reading an account from the 1745 Rising of a few men who showed up at some village wanting to fight for the Jacobite cause: It was clear they were desperately poor, as they were wearing only shirts and belted plaids.