Head-driven phrase structure grammar(HPSG)is a highly lexicalized, non-derivational generative grammar theory developed by Carl Pollard and Ivan Sag. It is a type of phrase structure grammar, as opposed to a dependency grammar, and it is the immediate successor to generalized phrase structure grammar. HPSG draws from other fields such as computer science( data type theory and knowledge representation) and uses Ferdinand de saussures notion of the sign. It uses a uniform formalism and is organized in a modular way which makes it attractive for natural language processing An HPSG grammar includes principles and grammar rules and lexicon entries which are normally not considered to belong to a grammar. The formalism is based on lexicalism. This means that the lexicon is more than just a list of entries, it is in itself richly structured. Individual entries are marked with types. Types form a hierarchy. Early versions of the grammar were very lexical ized with few grammatical rules(schema). More recent research has tended to add more and richer rules, becoming more like construction grammar. The basic type HPSG deals with is the sign. Words and phrases are two different subtypes of sign. A word has two features:/PHON/(the sound, the phonetic form)and/SYNSEM/(the syntactic and semantic information), both of which are split into sub-features. Signs and rules are formalized as typed feature structures 0.1.2 Functionalism L Definition Functional linguistics focuses on the analysis of the communicative functions of language rather than the language itself. For example at the front Participant Process Circumstance The N I Background Focus IL. Representative theories A. Lexical- functional grammar(词汇功能语法 Lexical functional grammar(LFG) is a grammar framework in theoretical linguistics, a variety of generative grammar. It is a type of phrase structure grammar, as opposed to a pendency gramma The development of the theory was initiated by Joan Bresnan and Ronald Kaplan in the 1970s, in reaction to the direction research in the area of transformational grammar had begun to take. It mainly focuses on syntax, including its relation with morphology and semantics. There has been little Lfg work on phonology(although ideas from optimality theory have recently been popular in LFG LFG views language as being made up of multiple dimensions of structure. Each of these dimensions is represented as a distinct structure with its own rules, concepts, and form. For example, in the sentence The old woman eats the falafel, the c-structure analysis is that this is a sentence which is made up of two pieces, a noun phrase(NP)and a verb phrase (VP). The VP is itself made up of two pieces, a verb (V) and another NP. The NPs are also analyzed into their parts8 Head-driven phrase structure grammar (HPSG) is a highly lexicalized, non-derivational generative grammar theory developed by Carl Pollard and Ivan Sag. It is a type of phrase structure grammar, as opposed to a dependency grammar, and it is the immediate successor to generalized phrase structure grammar. HPSG draws from other fields such as computer science (data type theory and knowledge representation) and uses Ferdinand de Saussure's notion of the sign. It uses a uniform formalism and is organized in a modular way which makes it attractive for natural language processing. An HPSG grammar includes principles and grammar rules and lexicon entries which are normally not considered to belong to a grammar. The formalism is based on lexicalism. This means that the lexicon is more than just a list of entries; it is in itself richly structured. Individual entries are marked with types. Types form a hierarchy. Early versions of the grammar were very lexicalized with few grammatical rules (schema). More recent research has tended to add more and richer rules, becoming more like construction grammar. The basic type HPSG deals with is the sign. Words and phrases are two different subtypes of sign. A word has two features: [PHON] (the sound, the phonetic form) and [SYNSEM] (the syntactic and semantic information), both of which are split into sub-features. Signs and rules are formalized as typed feature structures. 0.1.2 Functionalism I. Definition Functional linguistics focuses on the analysis of the communicative functions of language rather than the language itself. For example: (3) John sat at the front seat. Participant Process Circumstance Theme Rheme Given New Topic Comment Background Focus Ground Figure …… II. Representative theories A. Lexical-functional grammar （词汇功能语法） Lexical functional grammar (LFG) is a grammar framework in theoretical linguistics, a variety of generative grammar. It is a type of phrase structure grammar, as opposed to a dependency grammar. The development of the theory was initiated by Joan Bresnan and Ronald Kaplan in the 1970s, in reaction to the direction research in the area of transformational grammar had begun to take. It mainly focuses on syntax, including its relation with morphology and semantics. There has been little LFG work on phonology (although ideas from optimality theory have recently been popular in LFG research). LFG views language as being made up of multiple dimensions of structure. Each of these dimensions is represented as a distinct structure with its own rules, concepts, and form.For example, in the sentence The old woman eats the falafel, the c-structure analysis is that this is a sentence which is made up of two pieces, a noun phrase (NP) and a verb phrase (VP). The VP is itself made up of two pieces, a verb (V) and another NP. The NPs are also analyzed into their parts