2. Literature review
2.1. Four major analytic approaches that involve polysemy
A lexical item is presented in terms of a process of cognitive abstraction. In order to explain this process, the trend of semantic approaches is leaded by two principles, sometimes, with opposite viewpoints: first, generalization (or reducing) of polysemy, and second, distinction (or increasing) of polysemy. Depending on generalization, linguists try to generalize the discussion of polysemy in order to make an explanation of the theory more convincing. While, according to distinction, an accounting of the semantic details of polysemy, researchers try to find out as many distinctions as possible (Yale and Claudis, 2000). These diverse principles, classical approach, prototype approach, frame-based approach and relational approach provide four major different perspectives to polysemy and are introduced in the following sub-sections.
2.1.1 Classical approach
According to the classical approach, it is traditionally assumed that an individual entity is composed of a set of cognitive categories. For example, in the sentence,
John is a man, if John possesses a number of necessary and sufficient properties (also
features of this approach) that define the category man, he is a man. Following this concept, a new semantic explanation of the classical approach is developed by Katz (1972). He claims that when giving the sense of a word a conceptual schema should be provided rather than discussing the relationship of the meaning to the word.In this scheme, word knowledge is decomposed into numerous meaning features (which Katz called “conceptual categories”) by necessary and sufficient conditions.
In his principle, a lexicon consists of semantic components; and related senses might share some semantic features. For instance, chair might be decomposed into object and physical; besides, chair, bottle, and window may share the same semantic marker,
object. Moreover, in this schema, even a distinctive semantic feature could be a
significant hint to distinguish different senses of polysemous words.However, the principle of Katz’s claim brings about some problems of polysemy.
First, infinite semantic features may generate infinite senses. Further investigating Katz’s theory, Ravin (1990) proposes that “there are no clear criteria for which aspects of a real world situation are relevant to the semantics of a particular verb, but there is a methodology for determining which aspects ought to be semantically represented.”
Second, the classical approach does not emphasize how the semantic components can help us disambiguate polysemous words when different senses are realized in the same expression, that is, there is no mention about the syntactic behaviors of lexical items in the approach. Following Ravin’s statement, a methodology is necessary and will be given in the following section to define the senses of polysemous words.
2.1.2. Prototype approach
In the classical approach, the view of word meanings as consisting of necessary and sufficient conditions has been questioned, especially in the philosophy of language. For example, Wittgenstein (1958) claims:
The idea that in order to get clear about the meaning of a general term one
had to find the common element in all its applications has shackled philosophical
investigation for it has not only led to no result, but also made the philosopher
dismiss as irrelevant the concrete cases, which alone could have helped him to
understand the usage of the general term.
In Wittgenstein’s (1953) famous discussion of the meaning of the word game, he concluded that categories of meanings are familiarly resembled. This approach is further introduced in psychology by Rosch (1977). She demonstrated that people categorize objects not depending on necessary and sufficient conditions, but by relying on the resemblance of these objects to the prototypical members. In her studies, Rosch did find that people categorize objects by the concept of prototypes.
For example, in the Danni culture, they have only two color categories—one represents all light, warm colors and the other represent all dark, cool colors. Rosch found that in most conditions, they recognized prototypical red, yellow and white as being in the first category, and prototypical blue, and black in the second category.
Rosch also claimed that there are two prototypical models: in the first one, a single prototype contains the largest number of characteristic features and in the second one several prototypes each contain a different set of characteristic features. Linguists have adopted the second one to deal with polysemy.
With the concept of prototypes, Fillmore (1982) proposed one of the earliest discussions about prototypical meanings. He defined a word’s meaning by the components it resembles. When the meaning encompasses all of the components,
the use of the word is the most prototypical. When the meaning has none of the components, the use of the word is not prototypical. And when the meaning holds some of the components, the use of the word is peripherally prototypical. Taylor (1989) gives a more direct emphasis on connecting polysemy with the concept of prototypes: ‘if different uses of a lexical item require, for their explication, reference to two different domains, or two different sets of domains, this is a strong indication that the lexical item in question is polysemous.’ For example, school can be understood as the education of children as well as the administrative structure of a university which can be classified in different domains, thus, it can be viewed as a polysemous word. Further, Taylor adds another type of prototypical category—one without central meaning. For example, over can express a static relation of being vertical without contact with the reference, as in “the apple is over the table”; or a dynamic relation of being vertical without contact with the reference as in “the plain flew over the country.” In walk over the blocks expresses a dynamic relation without involving contact, and so on (Ravin and Leacock 2000). With these prototypical categories, word meaning is defined by the resemblance in the prototype. However, in this approach there is no clear discussion of how to distinguish the meanings of polysemous words.
2.1.3. Frame-based approach
In addition to prototype concepts, Fillmore et al (1992) proposed frame semantics in which a word’s meaning is defined by a cognitive frame—when one word’s expression is compatible in this frame, it denotes the meaning of this frame.
A frame is determined by our background knowledge and experience with the lexicon.
That is, a lexical meaning is identified by a structured cognitive schema in our mind.
Based on this notion, Fillmore built a frame-based online dictionary in which different senses of polysemous words are linked to various cognitive structures (or “frames”),
and the knowledge of the frame is encoded by the words. In his “frame-based”
approach, the concept of “frames” makes it helpful in reconsidering polysemy. For example, it is known that there are two senses of the verb RISK which are RISK as
“put at risk” and RISK as “face the risk of.” These two senses occur in different contexts where they are found in very different syntactic structures, thus, the two senses vary from each other by their specific syntactic behaviors. Therefore, different usages of the verb RISK might be necessary to help identify the specific sense of it. The interrelations between Frame and Syntax, thus, become a very important issue in Fillmore’s studies, and by this, a different concept of each sense helps distinguish polysemous words. Nevertheless, this approach still cannot account for the situation when the different senses of a polysemous word appear in the same expression.
2.1.4. Relational approach
Relation models are widely used to form a semantic network. In these models, words are organized depending on the semantic relations between their meanings.
Similar to the prototype approach, the relational approach also deals with semantic fields. Word relations according to this approach include Synonymy, Atonymy, Hypernymy, and Hyponymy and so forth. Synonymy can be defined as when two words can be substituted for each other in a context without changing the meaning of the clause. Atonymy is defined as substitution of two words in a context that have opposite meaning in the phrase. Hypernymy (superordinate relation), also called IS A relation is the linkage between lexical items in a specific-general relationship.
Hyponymy, the opposite relation to Hypernymy is the association between lexical items in a general-specific relationship. The relational approach is ideal for inferring, especially the transitive properties of word relation. For example, the hypernym of
book is publication, and the hypernym of publication is piece of work. Because of
the transitive relation, an assumption could be concluded that the hypernym of book is
piece of work.
Based on the relational approach, the online dictionary, WordNet (Fellbaum, 1998), was developed by George Miller and his colleagues at Princeton University.
As a source of related words for target sense in queries, WordNet indeed provides an improved solution. For example, looking up the word board in the noun hierarchy of WordNet, the ‘lumber’ sense of board could be detected by the hint of its related word