from 50% to 55%, significantly lower than the recorded 69% (Stuart & Majewski, 2015, p。 198) accuracy under normal usage。 Detail results of different thresholds in Appendix A。

2 Literature Review

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2。1 Views on Interpersonal Function

Functional Grammar identified three metafunctions of language – ideational metafunction that construes our human experiences; interpersonal metafunction that enacts our relationships with others; and textual metafunction that constructs our messages。 M。 A。 K。 Halliday (2008) defines interpersonal metafunction as the ‘language as action’ that interact with others via expressing the attitudes towards a person or an affair。 As the means to project the speaker or writer’s own angle on the value of the topic (Halliday & Matthiessen, 2008, p。 83), it usually carries considerable semantic load (Halliday & Matthiessen, 2008, p。 634)。

Under Halliday’s model, interpersonal metafunction can be classified into mood, modality, and evaluation devices。 Mood expresses interactional meaning via verbal exchange between the speaker and audience。 Modality can be further bifurcated to modalization and modulation based on modality type。 The former represents propositional probability and usuality, e。g。 “it is so”, “it isn’t so” and the intermediate “possible”, “sometimes”。 The latter refers to proposals, e。g。 “do it”, “don’t do it” and the intermediate “required to do”, “willing to do。” Figure 1 outlines Halliday’s model of interpersonal metafunction。

Figure 1 Halliday’s Model of Interpersonal Metafunction

Note。 Italics = Interpersonal Themes

In Halliday’s theory, evaluation devices, used to express one’s judgment or attitude to the content of the message (2008, p。 81), is regarded only as a supplement of modality (Li, 2011)。 Realizing the importance of evaluation, Li Zhanzi (2011) extended the model with Thomas Givón’s improved论文网

theory。 Under Li’s expanded model, instead of mood and modality, interpersonal metafunction is pided into a more balanced cognitive, evaluative and interactive3 aspects。 Cognition refers to the state of objectivity, meaning clause without emotional expression, e。g。 “The sun rises from the east,” while evaluation the state of subjectivity, includes sentimental expression, e。g。 “I love you。”

Li’s expanded model of interpersonal metafunction couples perfectly with theories in Natural Language Processing field。 The latter used Randolph Quirk’s (1985) concept of Private State – a state not open to objective observation or verification (Banea, Mihalcca, & Wiebe, 2015, p。 189) – to represent an intellectual and/or sentimental state。 Table 1 aims to parallel concepts in theories mentioned above。

Table 1 List of Parallel Concepts in Halliday’s, Li’s and Quirk’s theories

Halliday’s Model Li’s Expanded Model

Quirk’s in NLP Sentiment Analysis practice

Mood Interactive -

- Cognitive facts

Evaluation devices Evaluative Private State (subjectivity)

By studying how the Private States express and how its attributes work, NLP programs were able to detect the tendentiousness of the Private State, then calculate whether the clause is positive or negative (Banea, Mihalcca, & Wiebe, 2015)。