The Constructive Process Theory and
the Multi−Level Translation Method
 
      NTT Information Network
      Systems Laboratories
 
      Satoru IKEHARA*, Satoshi SHIRAI, Kentarou OGURA,
          Akio YOKOO and Hiromi NAKAIWA
 
    * NTT Information Network Systems Laboratories              1-2356 Take Yokosuka-shi Kanagawa-ken 238-03, Japan
     Tel:81-468-59-2515   Fax:81-468-59-3428
 
========================================================================
Abstract
  Computational linguistics has developed as a academic study, but a
means of dealing with existing linguistic processing, it is all but
useless and there are no examples of its having achieved appreciative
results. The basic reason for this is believed to be that computationallinguistics has historically segregated its contents from language and
has turned it into an abstract form as a problem of formality and theory.
  In the ALT-J/E Japanese into English Machine Translation System, a
critical posture is assumed toward the position of computational
linguitics. The system has suggested and realized a Multi-Level
Translation Method grom the view points of handling realistic language. This Method has been devised with the background of the Constructive
Process Theory which is one of the traditional Japanese grammar known
as the Tokieda Grammar. It features handling of subjective expression
which as aware of the speaker and thinks through the meaning of
expression structures. Technically, this method is supported by
meaning analysis which is based on linguistic knowledge. As linguistic
knowledge for meaning analysis, a word meaning dictionary consisting of
400,000 words and a semantic structure dictionary including 15,000
sentence type have been prepared. These have been written under a
system of about 100 types (in furtherdetail, these would amount 500
types) of syntactic attributes and about 3,000 types of semantic
attributes, If rules were to be written by the same atrribute system,
it would consist of such a structure that this knowledge would be
mobilized and translation be conducted.
 
========================================================================
1.Introduction
  Computational linguistics underwent development and progress since
generative grammar was propounded by Chomsky [Chomsky 1956, 1965]. 
Examples of this having achieved results in natural language processing
[Tomita 1987] were rare and the gapbetween reality remains large. A
great deal of thought has been directed toward identifying the causes
for this. In most cases, the impasse confronted by theory and
limitations are found in the initial presises of such theories.
  Primarily computational linguistics expresses language by a
theoretical model that has conformity and has sought to process this by
a unified method. Yet, in reality, lamnguage is certainly not anything
that abounds in such conformity. Natural language is something like a
custom or habit that has spomtaneously grown and developed within its
own group of languages. It reflects the anything but an object that is
perfectly and beautiflly adusted. It is a means of expression the
various distortions and conflicts in society. With the changes in
society, language itsself undergoes changes. Thus, to become
completely committed to language would make it impossible to pursuue
and unchangeable model. In contrast with natural language processing
attempts to grasp language as a method of reality, computational
linguistics would appear to separate itself from reality and become
involved with fictitious argument.
 
  For example, deep structure is suggested as a structural element of
linguistic model incomputational linguistics. But this is nothing
other than a sel-contradictory argument [Cresswell 1973, Mendeleson
1979 and Bresnan 1982] that ignores the relation between the target
objectives and the speaker in the language of reality. There is the
strange phenomenon of hypothesizing a meaning to enable explanation of
a meaning. Further, by manual translation, as in the saying,
"traslation begins with conversion of idioms to idioms" and importance
is attached to handling of idiomatic ecpressions. In contrast, in
computational linguistics, idioms tend to be rejected as being beyond
the scope of principles of compositional semantics. It would be
unnecessary to fall back on to the example of idiomatic expression, the
number of persons who believe that compositional linguistics is valid
in compositional semantics is limmited in number. Yet computational
linguistics continued to stand by steadfastly by this assumption.
 
 If languages are a social custom, there should be a method of
processing that matches them. Researches of natural language
processing require the pursuit of every one of these words.
 Accordingly, we have sought a new approach amidst the results of
conventinonal linguistics, promoting a new methodology. The background
for our research work is the Constructive Process Theory of language
[Tokieda 1941] by Motoki Tokieda, who followed up on the work initiated
in the 18th century by Norinaga Motoori[Motoori 1779]. Our machine
translation research efforts have been based on this theory and has
resulted in a Multi-Level Translation method[Ikehara et. al. 1987,
1989, 1989] and a test product Japanese to English experimental machine
translation system ALT-J/E.
  In this paper, thinking of the conventional computational lingustics
will be regarded in a critical manner and in its place, the
significance of the multi-level translation method based on the view
point of the processinf along this formula will be discussed.
 
2.Background of Linguistics
 2.1 Genealogy of Formalism
 (1)Background of Computational Linguistics
  There has been two types of logics, dialectic and formal logic since
the era of ancient Greece. Dialectics which was advanced by Hegel
[Muramatsu 1959] asserts that actual existence should be thought of as
a meaning theory. Hence, it deals with contents. On the other hand,
formal logic[Quine 1950] insisted on purity and handling of an ideal
world, and cut itself off from the realistic world.
  Symbolic logics[Hilbert et. al. 1928], computational logics[Allwood
1971] and computational linguistics are also derived from the latter,
formal logics. There appears an effort to apply computational
linguistics to natural language processing. But natural language is a
language that deals with the realistic world. This would seem to be
the cause of various problems. Especially, Frege's principle [Nomoto
1986], which is compositional semantics and constitutes a major
assumption in computational linguistic, is not valid in a natural
language.
 
 (2)Differences of View-points between Japanese and English
  Let us consider the differences between the Japanese and Ind-
European languages. The Ind-European languages have sentence patterns
such as 5 patterns which are relatively independent from contents. 
These languages can be classified as a suitcase type lamguage. 
Structualism was developed from the viewpoint of importance of forms
and structures of expressions. Chomsky took notice of the importance
of contents to overcome the limitation of structualism. But he still
inherited the basic problem of logics.
  In contrast, Japanese language is relatively free from forms and
does not have a rigid sentence structure. Japanese can be classified
as a 「furoshiki」(wrapping cloth) type language. Forms are dependent
on contents. In other words, the shape of contents appears in a form
of expression. Thus, contents are important in Japanese processing.
  There are 20 different types of grammars in Japanese. And four of
them are well known. Hashimoto Grammar and Tokieda Grammar form a
contrast. Hashimoto grammar[Hashimoto 1946] which was adopted for use
in school by the Ministry of Education of Japan is strongly influenced
by European philology. Tokieda grammar[Tokieda 1941] which was derived
from Norinaga Motoori[Motoori 1779] is the most traditional one.
  As nature is a complexed body of processes that develops with
conflicts as the motivating force, so also is language. Tokieda
established the Constructive Process Theory of language which placed
importance on the contents based on this idea.
 
 2.2 Outline of Constructive Process Theory of Language
 (1)Comparison to Generative Grammar
  Fig.1 shows the differences between the Constructive Process Theory
and Chomsky's basic concept.
  Constructive Process Theory asserts that a language should be
considered as a complex body of processes comprised of objects,
speaker recognition and expressions. Objects reflect recognition. 
This process is explained by the reflection theory. Recognitions are
combined into expressions using norms, namely the rule of languages. 
Linguistic norms are national rules which have been fostered in each
community. These norms are referred to as a grammar in the broad
meaning of the word.
 
         
         
         

Meaning = Relationship
 
         
         
         
                       
   
   
   

Object
 
 
 
 
 

Recognition
 
 
 
 
 

Expression
 
  
  
  
       
     
     
     

Reflection Theory
 
 
 
 

Grammar(Rule)
 
      
      
      
    a) Constructive Process Theory ( M.Tokieda )
 

   
 

Deep Structure
 
 
 
 

transfer
 
 
 
 

Surface Structure
 

     
 
    
    
    

Meaning
 
          
  
  
  

Expression
 
 
 
 
        b) Generative Grammar ( N.Chomsky )          
 
      Fig.1 Comparison between Generative Grammar         
         and Constructive Process Theory            
 
  In contrast, Chomsky interpreted language in the form of a dual
structure, a surface structure and a deep structure. The existence of
deep structure has been assumed as the meanings of surface structure. 
This is certainly a strange theory where because meanings are assumed
for the purpose of explaining meanings. More recently, he appears to
be attempting explanation based on mystic concepts. He says language
cannot be explained without assmuming that humans are born with a basic
linguistic ability.
 
 (2)Constructive Process of a Language
  Let us now see what happens when we regard language as a causal
sequence between object, recognition and expression. The world of
objects consists of a speaker and other objects. Objects are composed
from substances, attributes and relations. The speaker recognizes the
object world and at the same time, recognizes things about himself. In
recognition of objects, conceptualization takes place. 
 
[Object World]                            

          C:Conceptual
         
Self-Disunion
                 
 
 
 

Recognition
 
 
 
 

Expression
 
     
 (Subject)
     

Speaker
 
     
   B 
  Direct
        A       
    Object     Objective 
           Expression 
        C        
                 
    Subject    Subjective 
         B
  Expression 
                 
Subjective Expression: represent
  emotion and intention directly

Objective Expression: represent
  conceptualized objects
 
          A: Conceptua-
(Object)        lization 








 
 







 


 

Substance
 
 
 
 

Attribute
 


 
               
    
    
    

Relation
 
    
    
    
 
 
        Fig.2 Relation between Recognition and Expression
 










 
       
     
     








 
     
   






 

 
   
     
ブリスベン
  
  
行き






 





 





 

たい




 

だろう。




 

He
 

 

also
 

Brisbane
     

 

to
 

go
  

 

want
 

Probably
 
          
   
     
     
     
 
 
                                 
                                 
                     (Subjective)      
        (Objective) 
Direction






 

Substance
     






 

Addition 

Dynamic 
Attribute

 

Desire  

Guess  
 
 
     Fig.3 Processing of Subjective Expressions       
         and Objective Expressions            
 
  There are two occasions regarding recognition of self. One is the
occasion where speaker represents himself directly in the expression
without conceptualizing himself. On other ocassions, he conceptualizes himself and represent it as an object. When he conceptualizes himself, the phenomena of self disunion take place. A separate imaginary self
other than the actual self appears. And the self conceputualizes the
actual self.
  Recognition related to subjects and objects is represented by two
types of forms in linguistic expression as shown in Fig.3. One is a
subjective expression and the other is an objective expression. 
Subjective expressions represent speaker emotions and intentions. 
These expressions are expressed in the Japanese language by post
positionals and adverbs. Objective expressions represent conceptualized
objects. And these expressions are generally expressed by nouns and
verbs.
  This relation is somewhat different in English. Inflections usually express subjective expressions in English.
  A similar view is witnessed in the grammar of Port Royal[Lancelot et.al. 1660] in France 300 years ago. The difference is an important
factor in the translation method. 
 
3.Meaning and Meaning Processing
 3.1 Relational Meaning Theory
  Let us consider the structure of languages. If we assume that
meaning is a substance, it is one of either "object", "recognition" or
"expression" and the fourth element of "interpretation".
  If we say that meaning is born out of forms, we would arrive at a
"formal semantic theory". But this would be ideological. Next, if we
say that forms are born out of contents, this would result in a "object semantic theory" or "recognition semantic theory".
  If we assume that objects and recognitions are meanings, how should
we explain the sentence that has been erroneously written. This would
result in a sentence that is incorrect in which something that is
opposite is written, yet stating that the meaning is correct. Further, the object and recognition can never remain the same indefinitely and
will undergo changes. Then, the meaning of the sentence will change
independently from expressions. Motoki Tokieda chose eclecticism and
took meanings to be listener's reactions.
  Tsutomu Miura[Miura 1967] took after the Tokieda grammar, but
improved the theory and advocated the "relation meaning theory". He
proposed that structural processes from object to recognition are
combined to make an expression. He explained the meanings of
linguistic expression as the relationship between object, recogntion
and expression. This kind of relationship is concrete and specific. 
As long as the expression exists, so will the meanings. When
expression is cancelled out, so will all relationships, and the
meanings are also lost.
  The concept of regarding relationships as meaning resembles recent
situation semantics[Barwise et al. 1981], but actually, the two are
entirely different. In situation semantics, the meanings of
expressions and the meanings related to the location in which the
expression is placed are completely mixed up. The Miura grammar
features a clear distinction between linguistic expression and
expression of locations.
 
 3.2 Meaning Analysis and Meaning Understanding
 (1)Meaning Processing
  Meaning understanding would involve re-tracing such a relationship
between object, recognition and expression and to relive and experience the status of object and recognition.
  Here, let us consider meaning processing in two step. The first
step would be the process which designates the rules or conventions
used in linguistic expression. Conventions regarding languages are
complex and liable to be construed in many ways. The listener must
identify the convention used by the speaker. Let us define this act
of identifying the convention as "meaning analysis".
  The second step would be the process of identifying the recognition
of the speaker and the status of the object that is tied in with the
expression. Here, this action is refered as "meaning understanding". 
Thus meaning processing is comprised of two processes, "meaning
analysis" and "meaning understanding".
  The knowledge that is required for meaning analysis would be
linguistic knowledge, that is, conventions or norms regarding
languages. In contrast, meaning understanding would require knowing
the status of objects and this would require general knowledge, that
is, worldwide knowledge and knowledge in specialized fields.
 
 (2)Meaning Analysis
  Let us consider about the conventions involved in words of the
sentence (a). The meaning of the word "高い(takai)" is "expensive",
"high", "noble", "loud among others", but here, it is used with the
meaning "expensive". "Abura" has various conventions as "fat", "oil",
"lard", but here the convention expressing the meaning of "oil" is
used. Thus, meaning analysis is identification of the convention which
the speaker actually used among numerous conventions that exist in the
language.
 
   sono misewa takai aburawo utte  iru  
 (a) その店は  高い    売って いる。  
  that store expensive oil  sell         
 
  Meaning analysis cannot be achieved by merely staring at the words
one by one. Look at the sentence (b). Literal trnslation of
"senotakai" is "back is high". In English, one word "tall" is used to
convey this meaning. But looking at "back" and "high" separately will
not bring the concept of "tall". The same can be said of the other
expression. "Sell" and "oil" jointly means "idle away his time" in
this case. Thus, conventions regarding words can never be decisive if
they are thought out word by word.
 
 
   seno takai otokoga sigotochuu   aburawo utte  iru  
 (b)背の 高い 男が  仕事中     油を  売って いる。
    The tall man  during work hour is idling 
 
  Structrures of objects reflect themselves into speaker recognition.
These structures are also combined to expressions. This means that the
structure of an expressinon is a part of the meaning. Structures
cannot be separated from meanings because structures also represent
meanings. Thus, in meaning analysis also, there is the need to think
the relationship between structure and meanings. More specifically, it
is important to grasp the structure of expressions as units of meaning.
 
 (3)Meaning Understanding
  Next, let us consider about meaning understanding. As discussed in
the foregoing, meaning understanding involves the identification of the speaker's recognition and the status of object as tied in with the
expression.
  To know the speaker's recognition and the status of object, the
listener must be equipped with a certain world in his mind. This
world must have certain elements in common with the world which the
speaker is depicting. To restructure a world corresponding to the
expressions of the speaker, he will be required to link up the elements of the speaker's expressions and the elements of his own world. In
other words, meaning understanding can be considered as linking the
elements of the linguistic expressions and within the world model of
the listener. This action of linkage will structure a new portion in
the listener's world.
 
 3.3 Meaning processing and Knowledge
  In contrast that liguistic knowledge is required for meaning
analysis, meaning understanding will require worldwide knowledge. 
Compared to linguistic knowledge, worldwide knowledge is massive and
considerable amount of difficulties will be involved in research.
 
        
        

    Meaning Processing   
        
        
  

 
  

Syntax
Analysis

 



 



 

 Meaning
Analysis
 
 
 
 
 

Meaning   
Understanding

 



 



 

Intention
Extraction

 
 
 
 
 
                       
         
         
         
         

Language 
Knowledge

 
  
  
  
  

 World 
Knowledge

 
          
          
          
          
 
 
 
 
   
   

  Machine Translation 

[Infinite Object World]
 




 

  Query System 

[Small Object World]
 
       
       
       
       
       
       Fig.4 Meaning Processing and Application         
 
  In machine translation, the contents of source text to be translated are diversified and it would be difficult indeed to prepare a worldwide knowledge. Machine translation can be acceptable even if the computer
cannot entirely understand the contents of the text as long as the
translation results can be finally understood by humans. Replacing the
linguistic conventions used in the Japanese language by English
conventions and leaving it up to the judgment of the average person. 
This is the basic stance assumed by our research efforts in machine
translation. 
  First, we want to realize a translation based on meaning analysis. 
Next, we will extract the expressions and concepts which could not be
translated by meaning analysis and attempt a meaning understanding with a limited world model.
  It is advisable to deal with meaning processing with areas such as
telephone number information and database inquiries, because the target
world can be contracted into a comparatively small range. 
 
4.Multi-Level Translation Method
 4.1 Problems of Intermediate Language Method
  Conventional translation methods[MT Summit-I,II,V 1987,1989,1991]
can be classified into two types, the pivot method and the transfer
method. There are many which seek to achieve the pivot method. 
However, there have been none that can be stated to have truly realized
the pivot method. This is because universal intermediate language that
can be commonly applied to many language cannot be designed.
  Natural language has primarily originated by reflecting the
perspectives and thinking of the group of people using such language. 
It would appear unreasonable to consider a intermediate language that
would be commonly applicable to every language which differs in
thinking and perspective. 
  When a translation between languages which are very close each other is considered, or if a rough ranslation is to suffice, the pivot method may be satisfactory. But in either case, pivot method seems to have a
basic misunderstanding of languages in its background.
  The transfer method can be stated as being more realistic compared
to the pivot method, because it does not assume that intermediate
language is universal. However, if intermediate language can be
thought of as a meaning expression such as deep structure, the same
difficulties as in the case of the pivot method would arise. The
meanings of surface structure cannot necessarily be retained by deep
structure.
 
 4.2 Basic Concepts of Multi-Level Translarion Method
  The method of translation based on the foregoing meaning analysis is the Multi-Level Translation method. The term "Multi-Level" indicates
that translation is being conducted at various levels of abstraction.
  The need to observe differences between subjective expression and
objective expression have previously been mensioned. And, the
necessity of consideration about the meaning of structures have also
been pointed out. The Multi-Level Translation method has been
structured based on these two factors.
  The first point is considered as follows. Japanese and English are
very different in presenting subjective expressions. Therefore,
subjective expressions are segregated from objective expressions and
converted into English.
  The second point is resolved by abstraction of expression structures.Three levels of abstraction have been proposed. The first is related
to a level of idiomatic expressions. The second concerns specific
structures such as loosely coupled words. The last concerns most
loosely coupled structure that can be represented by general rules.
 
 
 
  
  

Japanese
 
               

 

English 
 
    
    
    
                                   



 

 Sentence
Analysis
 

Separation and Recombination
Method for the Subjective
Expression

Sentence
Synthesis
 
   
   
   
   
 
 
Subjective
Expression
Transfer 

 
 

    
    
    

Subjective
Expression

 

 
 
 

 
 
 

Subjective
Expression

 

    
    
    
 



   
   
   
  
                       
 
 
 
 

Objective
Expression

 

 
 
 








 

@Idiomatic E. T.
 








 

 
 
 

Objective
Expression

 
   
    
    
    

ASemantic V. P. T.
 
         
  Multi-Level 
  Transfer Method
         
         
         
@Idiomatic Expres
 -sion Transfer
ASemantic Valentz   
 Pattern Transfer   
BGeneral Pattern    
 Transfer       

BGeneral P. T.  
 
 
      Fig.5 Multi-Level Translation Method           
 
Thus, this system is divided up into 2 major conversion paths. The
one is the conversion of the speaker's sense or what is subjective. 
The other is the path for conversion of the description for the object. And this path splits up into 3 more paths, depending on the abstraction degree in conceptualizing objects. Thus, the Multi-Level Translation
method has currently four translation paths. 
 
 4.3 Organization of Knowledge
 (1)Machine Translation and Knowledge
  To realize a machine translation system, a knowledge of language is
essential. Natural language processing can be stated as being a battle
with ambiguity from the beginning to end. In the translation process,
various types of ambiguities arise, but this is regarded as being a
lack of knowledge that is required. 
  To overcome such ambiguity, it is necessary to study what knowledge
is lacking and to have such knowledge established as the rule or as a
dictionary. It is important to consider the type of ambiguity and
relationship with the knowledge corresponding to it. ALT-J/E system
placed importance on knowledge for meaning processing for the purpose
of solving ambiguity of sentence structure and of the meaning of
individual words.
  From the viewpoint of linguistic knowledge, linguistic conventions
are divided into those which are related to subjective expressions and
those related to objective expressions. Of the two, the knowledge
related to subjective expressions are smaller in scale compared to
objective expressions and have been solved in terms of rules or
programming. But the objective expressions being massive, we have
decided to compile them in the form of a dictionary.
 
 (2)Semantic Word Dictionary and Semantic Structure Dictionary
  When the speaker expresses an object, abstraction is conducted and
the objectis conceptualized. In language expressions, the concept of
object is expressed separately in terms of a concept of substance and a
concept of attribute. Linguistic conventions which combine concepts to
expressions have therefore been compiled into 2 separate dictionaries,
a semantic word dictionary consisting of 400,000 words and a semantic
structure dictionary consising of 15,000 sentence forms.
 
                 
     

  Semantic Word Dictionary 
  
  
  
  
  
  

Semantic Attribute
System
   
   
   
   

Caption Words  400,000
  < Total Word 600,000>  

 

・General Noun    
 2,800 Categories
・Proper Noun     
   200 Categories
 
                   
   
   
   
   

Semantic Structure Dictionary
  
  
  
  
  
  

    15,000 Rules
Prepared for Declinable Words
 
                 
 
                
       Fig.6 Knowledge for Meaning Analysis
 
  The meanings of words and their translation are listed in ordinary
dictionaries. But it does not serve to have the computer know how
they are to be used. For example, the word "school" is used as a
"place" and also as an "organization". As a means of desscribing these
knowledge, we have compiled the use of the meaning of words as a
semantic attribute system. 
  Consider the relation between expression structures and meanings. 
The meanings of expressions are not necessarily represented by the sum
of the meaning of every word in the expression. In fact, it would
appear that the meanings of linguistic expressions actually used cannot
be explained solely by the meaning of each word used in the expression.
Expression structures need to be considered as units of meanings in
natural language. Based on such thinking, the abstraction of
expression structures centered around declinable words and compiled as
units of meanings has resulted in the semantic structure dictionary. 
 
 (2)Necessity of Detailed Meaning Attribute System
  It is important to consider precision of knowledge description in
relation to the degree of ambiguity. For example, an algorithm which
was valid in a world of 1,000 words may not necessarily be valid in a
world of 100,000 words. Experiences indicate that increase of the
number of words causes rapid growth of ambiguities. 
  Seeking to establish practical method, we have collected words
including proper nouns normally used day to day and have compiled a
dictionary of about 400,000 words. Thus, it is necessary for semantic
attribute system to work with this environment. We began with about
500 categories. But this has resulted in that translation of verbs
cannot be precisely described. With the consideration of our aim and
environment, we set up 2,800 categories for general noun semantic
attributes and 200 categories for proper noun semantic atrributes.
  Here, let us look at the differences of description capabilities
between of our semantic attribute systems and other similar systems.
Case 1 is a typical example of Japanese to English machine translation
systems. The number of semantic categories are between 30 to 50. Case
2 is the current plan of EDR [EDR 1990]. Case 3 is an example of our
translation system ALT-J/E.
  A comparison was made of the three cases. And, the capabilities of
describing the translation rules for verbs are evaluated. In the
comparison, the case of ALT-J/E has been assumed to be 100%.
 
     Table 1 Comparision of Semantic Attribute System   


No


 Case

 No. of
Categories

No. of
words

Evaluation
(Example*)


 

Current System
(J. to E.)

30−50
Categories

 50,000
  Words

 31%
 


 

EDR
Project**

  500
Categories

400,000
  Words

 59%
 



 

ALT−J/E

 

3,000
Categories
 

400,000
  words
 

100%
(Assumed)
 
    * Relative Amount of Writable Semantic Patterns    
     (Valentz Pattern) for Japanese General Verbs    
    ** Japan Electronic Dictionary Reseach Institute, Ltd. 
 
  The results of this comparison are as follows. The capabilities of
description was 31% for case 1 and 59% for case 2. Those results
indicate that when precision levels of semantic atrributes are low,
many essential rules cannot be written. Our experiences also indicates
that, in Japanese to English machine translation, precision level for
some 3,000 types of semantic attributes are necessary for
differentiation of translation for verbs. However, this is not
sufficient for translation of nouns.
 
5.Summary
  In machine translation research, some of the main problems include
the meaning (convention) in which each word is being used (words that
are frequently used have many meanings), the distinction between
idiomatic and literal meanings, the sentence form in which sentences
with no subjects (or subject matter) and multiple sentences. The
achievements of conventional computational linguistics is all but
helpless in dealing with realistic problems. When natural language is
viewed as having developed as a natural phenomenon and as a social
custom, there is a different convention regarding the meaning and
method of use for each and every word. The convention needs to be
discovered and compiled as a knowledge if we are to realize natural
language processing This does not mean collection of knowledge to
match the algorithm to match knowledge [Nirenburg 1989].
  Based such thinking, this paper points out the @roblems confronted
by conventional computational lingfustics, and discusses the
significance of a new machine translation system, the multi-level
translation method.
  As a concept, the multi-level translation method has been devised
with the background of the constructive process theory which is one of
the traditional Japanese grammar known as the Tokieda Grammar. It
feature handling of subjective expression which is aware of the speaker
and thinks through the meaning of expression structures. Technically,
this method is supported by meaning analysis which is based on
lingustic knowledge. As lingustic knowledge for meaning analysis, a
word meaning dictionary consisting of 400,000 words and a semantic
structure dictionary including 15,000 sentence types have been
prepared. These have been written under a system of about 100 types
(in further detail, these would amount to 500 types) of syntactic
attributes and about 3,000 types of semantic attributes. If rules were
to be written by the same attribute system, it would consist of such a
structure that this knowledge would be mobilized and translation be
conducted.
 
 The ALT-J/E has, by means of this system, accomplished new functions,
including,
(1)Differentiation in the translation of the verb and noun
(2)Automatic rewiting function of original Japanese sentences
   which reduces the number of verbs
(3)Automatic supplementation of subjects and objects
These functions are mandatory in realizing a system of Japanese to
English machine translation that requires no pre-editing.
 
  The main issues confronted by machine translation research are:
(1)Meaning Analysis of Complex Noun Phrases and Complex Compound Nouns,
(2)Selection of Determiners and
(3)Global Structure Generation of English for long sentence translations.  Our major research efforts are being concentrated in these areas. 
Future research targets will be:
@Multi-Dimension of Semantic Categories,
AAnalysis of Speaker's View Point,
BStructure of Recognition,
CIntroduction of Common Sense about the World. 
  Preparations for these studies are now under way.
 
=Acknowledgement=
The authors wish to thank Dr. M. Miyazaki, Professor of Niigata
University and other colleagues of machine translation for their
valuable contribution to discussions.
 
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  Linguistics, Cambridge Univ. Press, 1971
 
[Barwise et al. 1981] J. Barwise and J. Perry:"Situation and Attitudes",  J. of Philosophy, Vol.78, pp.668-691
 
[Bresnan 1982] J. Bresnan ed.:"The mental Representation of Grammatical
  Relations", Cambridge, Mass., The MIT Press, 1982
 
[Chomsky 1956] N. Chomsky:"Three Models for the Description of Language",  IRE Trans, IT-2, 1956
 
[Chomsky 1965] N. Chomsky:"Aspects of the theory of Syntax", MIT Press,  1956
 
[Cresswell 1973] M.J. Cresswell:"LOGICS AND LANGUAGES", Methuen Co. Ltd.,  London, 1973
 
[EDR 1990] EDR:"Concept Dictionary", Technical Report-027, Japan
  Electronic Dictionary Research Institute, Ltd., April, 1990
 
[Hashimoto 1946]S. Hashimoto:"Theory of Japanese Language: Kokugogaku
  gairon(in Japanese)", Iwanami Bookstore, 1946
 
[Hilbert et. al. 1928] D.Hilbert and W. Akermann:"Grundzuge der
  theoretischen Ligik" Translator M. Itou, Oosaka kyouiku Book, 1928
 
[Ikehara et al. 1987] S. Ikehara, M. Miyazaki, S. Shirai and Y. Hayashi:  "Speaker's Recognition in Language and Multi-Level Translation
  Method (in Japanese)", Transaction of Information Society of Japan,
  Vol.28, No.12, 1987
 
[Ikehara 1989] S. Ikehara:"Multi-Level Machine Translation System",
  Future Computer Systems, Vol.2, No.3, pp.1269-1279, 1989
 
[Ikehara et. al. 1989] S. Ikehara, M. Miyazaki, S. Shirai and A.
  Yokoo:"An Approach to Machine Translation Method Based on
  Constructive Process Theory", Review of ECL, Vol.37, No.1, pp.34-49,
  1989
 
[Lancelot et. al. 1660] C. Lancelot and A. Arnauld:"Grammaire g'en'erale  et raisonn'ee, les fondements de l'art de parler", Chez Pierre le
  Petit, Paris,1660
 
[Mendelson 1979] E. Mendelson:"Introduction to Mathematical Logics",
  D. Van Nostrand Company, 1979
 
[Miura 1967] T. Miura:"Theory of Recognition and Language (in Japanese)",  Keisou Shobou, 1967
 
[Motoori 1779] N. Motoori:"kotoba no tama-no-o (in Japanese)", 1779 =
  see S. Oono: "Complete Works Series of Motoori Norinaga (in Japanese),  Chikuma Publishing, 1970
 
[MT Summit-T 1987] Proc. of MT Summit-T, Sept.16-18, 1988
 
[MT Summit-U 1989] Proc. of MT Summit-U, Aug.16-18, 1989 
 
[MT Summit-V 1989] Proc. of MT Summit-V, Jul.2-5, 1991 
 
[Muramatsu 1959] K. Muramatsu:"Logics of Hegel(in Japanese)", Keisou
  Publishing, 1959
 
[Nirenburg 1989] S. Nirenburg:"KBMT-89-A Knowledge-Based MT Project at
  Carnegie Mellon University", Proc. of MT Summit-II, pp.141-147
 
[Nomoto 1986] K. Nomoto:"Frege's Philosophy of Languages(in Japanese)",  Keiso publishing, 1986
 
[Quine 1950] W.V. Quine: "Methods of Logic" Translator Nakamura and
  Oomori, Iwanami Bookstore, 1961
 
[Tokieda 1941] M. Tokieda:"The Principle of Linguistics (in Japanese)",  Iwanami Bookstore, 1941
 
[Tomita 1987] M. Tomita:"An Efficient Augmented-Context-Free Parsing
  Algorithm", Computational Linguistics, Vol.13, No.1-2, pp.31-46
 
 
 
  Nevertheless the progress of computstional linguistics for these
30 years, they are not useful yet for practical language processing
and there are no example where noticeable effects are obtained. The
reasons are considered that they historically cut off the actual
contents from languages and have focused the attention on the
relation between form and rogic of expressions.
残り
[ALPAC 1966]
Alpac Report:"Language and Machines: Computers in Translation and
Linguistics", Automatic Language Processing Advisory Committee,
National Academy of sciences, U.S. National Research Council, 1966
 
[Fillmore 1975]
C.J. Fillmore:"TOWARD A MODERN THEORY OF CASE & OTHER ARTICLES (in Japanese)", Sanseidou Publishing, 1975
 
[Nagao 1985] 
M. Nagao:"Evaluation of the Quality of Machine-Translated Sentences and
the Control of Language", J. of Information Processing Society of
Japan, Vol.26, No.10, pp.1197-1202
 
[Nagao 1989]
M. Nagao:"Japanese View of Future of Machine Translation", Proc. of MT
Summit-II, pp.123-140
 
[Saussre 1909]
F.D. Saussure:"COURS DE LINGUISTIQUE GENERALE", Japanese Edition,
Keisou Publishing
 
[Tomabechi 1987]
H. Tomabechi:"Direct Memory Translation", 'Proceedings of IJCAI-87'