His colleagues always pay him compliments on his eloquent and persuasive speeches at conferences.

pay 在这里是动词，意思是"给予、付出"，常用于表示给予某种形式的关注或表达。 compliments 是名词 compliment 的复数形式，意思是"称赞、恭维"，指表达赞美或欣赏的话语。 pay compliments 是一个固定搭配，意思是"给予称赞"或"说赞美的话"。