Identifers for text and flashbacks

My wife and I have been watching your dramas every night for years.  We are totally dependent upon English subtitles.  Two things occur in every episode of every drama that are easily misunderstood:  (1) The subtitle text when the actor is thinking to himself rather than speaking out loud, and (2) flashbacks. 

Each of these should have a visual marker so that the viewer knows what he is seeing. 

A visual marker for the subtitle text of the actor thinking to himself rather than speaker out loud is easy:  just put the text in italics. 

A visual marker for a flashback could be a different color -- B&W or a yellowish cast -- or even the word "flashback" displayed in the upper corner of the screen.  Your technicians are surely more adept than me of finding an appropriate and workable visual. marker.  I request that they do so. 

Best,

Ed Moats