This is the 12801st most frequent Korean word.
데얀
"데얀" (Deyan) is a proper noun, typically used as a masculine given name of Slavic origin.
Here, '데얀' is used as a proper noun representing a person's name, likely referring to someone's specific skill.
데얀이 한국어를 잘해요.
Dae-yan speaks Korean well.
In this sentence, '데얀' is again used as a proper noun referring to an individual's name and their profession/status is being discussed.
데얀은 축구 선수로 유명합니다.
Dae-yan is famous as a soccer player.
Here, '데얀' is the name of a person, and the sentence refers to performing an action (studying) with him.