19. The method of claim 15 , the reproducing step includes reproducing the text data by applying a different style to the specific portion of the text data, the different style being specified by at least one of a font identification, a font style, a font size, and a font color defined in the inline style information, the different style being different from the default style defined in the region style information.
15. A method of reproducing text subtitle stream recorded on an optical disc, the method comprising: reading, from the optical disc, a playlist including at least one playitem and at least first and second subplayitems, the playitem specifying a time based playing interval from in time until out time associated with at least one audio/video (AV) stream file including at least one audio/video (AV) stream and the first subplayitem specifying a time based playing interval from in time until out time associated with at least one text subtitle stream file including at least one text subtitle stream; parsing the text subtitle stream into a first segment and a second segment, the first segment including region style information including a default style to be applied to a text subtitle region of a display screen by default, the second segment including text data to be displayed within the text subtitle region of the display screen and inline style information to be applied to a specific portion of the text data which overrides the region style information; and reproducing the text data by applying at least one of the region style information and the inline style information, wherein the first subplayitem indicates a plurality of independent text subtitle stream files having different language codes, respectively, and wherein the first subplayitem is associated with reproduction of the text subtitle stream and is synchronized with the playitem, and the second subplayitem is associated with reproduction of browsable slideshow and is not synchronized with the playitem.