A topic marker is a grammatical particle used to mark the topic of a sentence. It is found in Japanese, Korean, Sorani, Quechua, Ryukyuan, Imonda and, to a limited extent, Classical Chinese. It often overlaps with the subject of a sentence, causing confusion for learners, as most other languages lack it. It differs from a subject in that it puts more emphasis on the item and can be used with words in other roles as well.