Abstract: Halliday's Functional Grammar regards adverbials as Adjuncts，which are classified into circumstantial Adjuncts，modal Adjuncts and conjunctive Adjuncts.Modal Adjuncts are further divided into mood Adjuncts and comment Adjuncts.Comment Adjuncts are a kind of interpersonal Adjuncts，so they express interpersonal meaning.Such a kind of interpersonal meanings comes from the speaker，therefore it is a kind of speaker meaning.This makes it clear that comment Adjuncts are speaker-oriented in nature.The interpersonal meanings conveyed by comment Adjuncts include engagement meaning，epistemic meaning and evaluative meaning.Engagement meaning refers to the manner in which the speaker conveys the information.Epistemic meaning includes judgmental meaning and evidential meaning.The former expresses the speaker's judgment of the certitude of truth-value of the proposition，while the latter conveys the speaker's evidence to the reliability of the propositional information.Evaluative meaning refers to the speaker's evaluation of the proposition as a whole or his evaluation of the Subject's role in the propositional event.What is more important，all these interpersonal meanings are dependent on the speaker's subjective attitude towards the communicated information，therefore they embody obvious speaker's subjectivity.