特别 (tèbié) can be an adjective meaning 'special, unusual' or an adverb meaning 'especially, very'. As an adjective, it is more common in everyday speech than 特殊 (tèshū), which is more formal and used in technical contexts. As an adverb, 特别 is the most general word for 'especially'; 尤其 (yóuqí) often introduces a specific example (尤其…), and 格外 (géwài) emphasizes 'exceptionally' or 'more than usual'.