Metalingual (metalinguistic) function: the function of language that can be used to talk about language itself.

元语言功能，指语言可用来讨论语言本身的功能。

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Somebody says, "What is a mare?" "Well, it's a female horse." "Well, it's a female horse" is the metalingual function.

有人问“什么是母马“，“母马就是雌性的马“,“母马就是雌性的马“这句话就是元语功能。

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Notice that the relationship between the rhetorical is and the grammatical is is basically the relationship between what Jakobson calls the "poetic function" and the "metalingual function."

注意下,修辞学上的is和语法中的is之间的关系,基本上就是雅各布森所说的,“诗功能“和“元语言功能“之间的关系“

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