Marilyn Monroe struggled to beat a stutter, and her breathy, ethereal vocal styling was arrived at with assistance from a speech therapist as a software to assist her overcome her stutter.
It largely labored, although her stutter did come again with a vengeance in her later years, and a few speculated that the added stress of its return was her undoing.
Regardless, the online impact of that breathy tone gave a form of whispered edge to sure phrases which made her accent sound related at instances to a Spanish accent.
On this 1955 radio interview, hearken to how she responds to the interviewer at across the 40 second mark when she says, “Do not let ’em idiot you. I am not.”
Marilyn Monroe had a reasonably distinctive accent that was a product of each the period and her speech remedy. Ana de Armas sounds superb to me.