ABSTRACT
Semantic types reflect the categorization of a language and therefore must be taken into consideration in classifying parts of speech. The expressional functions used as the essence of parts of speech refer to the meaning representation pattern of a word, including the four basic types: statements, references, substantive modifications and predicate modifications. The classification of parts of speech according to the distribution of a word is only a convenient theory. The parts of speech of a word are inferred from its distributive characteristics and already exist before “being classified into them”. Although expressional functions are the intrinsic bases for classifying parts of speech, they are not directly observable and therefore cannot be used as criteria for classifying parts of speech. Grammatical functions that have equal classification values are collected into clusters, with each equivalent function cluster representing one part of speech. The classification criteria are selected from the equivalent function cluster of a part of speech.
