Semantic And Syntactic Features Of Have(got)to Under Different Semantic Gradients

Word sense disambiguation is a kind of means to describe the semantic or syntactic features of English quasi-modal verbs have(got)to in the specific context and determine the senses of have(got)to.This method has been widely used in the natural language processing area and has achieved great outcomes.Moreover,this method is significant to the machine translation,documents retrieval,speech recognition and linguistics.As important means to express human`s emotions and attitudes,senses of modality has the characteristics of indeterminacy.According to Coates(1983)The Semantics of Modal Auxiliaries,the indeterminacy can be divided into gradience,ambiguity and merger.On the basis of word sense disambiguation,this research studies the semantic and syntactic distribution features of English quasi-modal verbs have(got)to under different semantic gradience restrictions.Firstly,this thesis starts from the meaning division of have(got)to and the annotated 2.5 million corpora.Furthermore,this research has calculated the mutual information of have(got)to and its adjacent subjects and predicates.Moreover,to establish the formal context of have(got)to,this research adopts twelve semantic features and four syntactic features for word sense disambiguation.This study selects sample sentences for training group and testing group to build the word sense disambiguation model.The results show the accuracy of the training group is 91.5% and testing group is 81.3%,which proves the scientificity of this research.The sense gradience indeterminacy of modal verbs is a gradually transition from one sense to another sense,which does not have distinct boundaries among the senses.This cline modality meaning from core to border forms the sense gradience of modal verbs.This research concludes and adjusts Lyons and Coates(1980)classifications standards of sense gradience and classifies four gradience layers of sense gradience restriction have(got)to: human constraint,human institution,human code and natural law.This thesis extracts nine syntactic features and three semantic features which influence the sense gradience have(got)to.Through the APOSD,the sense gradience model of have(got)to finally has been established.The research results are as follows: The agent verb and patient verb tend to classify the four gradiences in a connotative standard.Moreover,the attribute mental verb and three senses of have(got)to are in the lowest layer,which simplifies the sample sentences specifically.Root necessity have(got)to has the highest frequency in the natural law gradience layer.Root obligation have(got)to and epistemic necessity have(got)to have the lowest occurrence in the natural law gradience layer.Root obligation have(got)to has the highest rate in the human institution gradience.Epistemic necessity have(got)to has the highest frequency in the human code gradience layer than other two senses.Second person subject influences the human constraint gradience most,third person subject has the high frequency in the natural law and human institution gradience layer.First person subject has relatively high frequency in the human code gradience layer.Agent verb appears at most in the human constraint gradience while patient verb appears the most in the natural law gradience.As for the animate or inanimate subject,along with the gradience from human constraint to natural law the animate subjects decrease while the inanimate subjects increase.This thesis adopts the formal concept analysis theory to study the word sense disambiguation and the semantic and syntactic features under different sense gradience restrictions of quasi-modal verbs have(got)to,which enriches the study scopes of modality and offers references for the knowledge discover studies relating to semantics.