Comparative forms are used in grammar to compare two or more things. They often involve adjectives or adverbs that change to show differences in qualities, such as tall becoming taller or fast becoming faster. This helps to clarify how one item is different from another in terms of a specific characteristic. In English, comparative forms typically add "-er" to one-syllable words, while for longer words, "more" is used before the adjective, like beautiful becoming more beautiful. These forms are essential for making comparisons clear and precise in both spoken and written communication.