1. A method for displaying caption data in a device, the method comprising: receiving content data including video data; if original caption data is included in the content data, performing error checking for the original caption data and generating corrected caption data by correcting one or more errors of the original caption data; extracting one or more high-difficulty words from the corrected caption data; generating explanation data corresponding to each of the one or more high-difficulty words, wherein the explanation data includes data for explaining each of the one or more high-difficulty words; determining at least one special effect corresponding to at least one word included in the original caption data or the explanation data, wherein the at least one special effect includes vibrations, color light, heat, chill, or fragrance corresponding to the at least one word included in the original caption data or the explanation data; and while displaying the video data, simultaneously providing the corrected caption data, the explanation data, and the at least one special effect.