Morphological mismatches in machine translation

This paper addresses one of the least studied, although very important, problems of machine translation—the problem of morphological mismatches between languages and their handling during transfer. The level at which we assume transfer to be carried out is the Deep-Syntactic Structure (DSyntS) as proposed in the Meaning-Text Theory. DSyntS is abstract enough to avoid all types of surface morphological divergences. For the remaining ‘genuine’ divergences between grammatical significations, we propose a morphological transfer model. To illustrate this model, we apply it to the transfer of grammemes of definiteness and aspect for the language pair Russian–German and German–Russian, respectively.     

Regular Languages Defined by Generalized First-Order Formulas with a Bounded Number of Bound Variables

Abstract. We consider generalized first-order sentences over < using both ordinary and modular quantifiers. It is known that the languages definable by such sentences are exactly the regular languages whose syntactic monoids contain only solvable groups. We show that any sentence in this logic is equivalent to one using three variables only, and we prove that the languages expressible with two variables are those whose syntactic monoids belong to a particular pseudovariety of finite monoids, namely the wreath product of the pseudovariety DA (which corresponds to the languages definable by ordinary first-order two-variable sentences) with the pseudovariety of finite solvable groups. This generalizes earlier work of Thérien and Wilke on the expressive power of two-variable formulas in which only ordinary quantifiers are present. If all modular quantifiers in the sentence are of the same prime modulus, this provides an algorithm to decide if a regular language has such a two-variable definition.     

Regular Languages Defined by Generalized First-Order Formulas with a Bounded Number of Bound Variables

Abstract. We consider generalized first-order sentences over < using both ordinary and modular quantifiers. It is known that the languages definable by such sentences are exactly the regular languages whose syntactic monoids contain only solvable groups. We show that any sentence in this logic is equivalent to one using three variables only, and we prove that the languages expressible with two variables are those whose syntactic monoids belong to a particular pseudovariety of finite monoids, namely the wreath product of the pseudovariety DA (which corresponds to the languages definable by ordinary first-order two-variable sentences) with the pseudovariety of finite solvable groups. This generalizes earlier work of Thérien and Wilke on the expressive power of two-variable formulas in which only ordinary quantifiers are present. If all modular quantifiers in the sentence are of the same prime modulus, this provides an algorithm to decide if a regular language has such a two-variable definition.     

机器翻译中异化现象的分析及映射运算

本文从词汇－语义角度分析了机器翻译中与汉英语言相关的一些异化现象，探讨了语义－句法映射运算集的有效性和合理性．同时，本文讨论了通过变异映射集、变异类型指示器和参数合一机制解决机器翻译中异化现象的方法．这些方法提高了译准率，使生成的句子既能正确表达原中间语言的语义，又符合目标语言的表述习惯．     

Multilingual generation: The role of telicity in lexical choice and syntactic realization

Multilingual generation in machine translation (MT) requires a knowledge organization that facilitates the task of lexical choice, i.e. selection of lexical units to be used in the generation of a target-language sentence. This paper investigates the extent to which lexicalization patterns involving the lexical aspect feature [+telic] may be used for translating events and states among languages. Telicity has been correlated syntactically with both transitivity and unaccusativity, and semantically with Talmy's path of a motion event, the representation of which characterizes languages parametrically.Taking as our starting point the syntactic/semantic classification in Levin's English Verb Classes and Alternations, we examine the relation between telicity and the syntactic contexts, or alternations, outlined in this work, identifying systematic relations between the lexical aspect features and the semantic components that potentiate these alternations. Representing lexical aspect — particularly telicity — is therefore crucial for the tasks of lexical choice and syntactic realization. Having enriched the data in Levin (by correlating the syntactic alternations (Part I) and semantic verb classes (Part II) and marking them for telicity) we assign to verbs lexical semantic templates (LSTs). We then demonstrate that it is possible from these templates to build a large-scale repository for lexical conceptual structures which encode meaning components that correspond to different values of the telicity feature. The LST framework preserves both semantic content and semantic structure (following Grimshaw during the processes of lexical choice and syntactic realization. Application of this model identifies precisely where the Knowledge Representation component may profitably augment our rules of composition, to identify cases where the interlingua underlying the source language sentence must be either reduced or modified in order to produce an appropriate target language sentence.     

Interlingua-based English–Hindi Machine Translation and Language Divergence

Interlingua and transfer-based approaches tomachine translation have long been in use in competing and complementary ways. The former proves economical in situations where translation among multiple languages is involved, and can be used as a knowledge-representation scheme. But given a particular interlingua, its adoption depends on its ability (a) to capture the knowledge in texts precisely and accurately and (b) to handle cross-language divergences. This paper studies the language divergence between English and Hindi and its implication to machine translation between these languages using the Universal Networking Language (UNL). UNL has been introduced by the United Nations University, Tokyo, to facilitate the transfer and exchange of information over the internet. The representation works at the level of single sentences and defines a semantic net-like structure in which nodes are word concepts and arcs are semantic relations between these concepts. The language divergences between Hindi, an Indo-European language, and English can be considered as representing the divergences between the SOV and SVO classes of languages. The work presented here is the only one to our knowledge that describes language divergence phenomena in the framework of computational linguistics through a South Asian language.     

Lexical paraphrases in multilingual sentence generation

We describe the architecture of a sentence generation module that maps a language-neutral deep representation to a language-specific sentence-semantic specification, which is then handed over to a conventional front-end generator. Lexicalization is seen as the main task in the mapping step, and we specifically examine the role of verb semantics in the process. By separating the various kinds of knowledge involved, for related languages (such as English and German) the task of multilingual sentence generation can be treated as a variant of the monolingual paraphrasing problem.     

A two-layered interface architecture

The problems of interfacing to external subsystems and using multiple paradigms in a single software system center on resolving the impedance mismatch (the differences in the data models and thought patterns of each paradigm) and how to reflect the differences across the language boundary. One technique is to build an interface between the two paradigms. The interface should strive to resolve the mismatches while providing access to those language features valuable to the problem solution. This means that semantic issues as well as syntactic issues must be addressed. Features of the implementation languages that contribute to the mismatch need to be identified and examined in order to develop a solution. This paper describes a two-layer architecture based upon the idea of abstract interfaces. This architecture appears to provide a basis for interfacing programming languages to object databases which addresses the semantic gap, or impedance mismatch, between the two as well as the syntactic differences.     

Formal syntax methods for natural language

This paper describes on-going research into the applications of some techniques normally used to formally specify and analyze the context-sensitive syntax of programming languages to the specification and analysis of the syntax of a natural language, namely English. The specific formal methods presently being investigated are two-level grammar (2LG) and the Vienna Definition Language (VDL). A preliminary subset of English has been established consisting of fifteen basic sentence patterns. 2LG and VDL specifications are given for one of these sentence types and the syntactic analysis of an English sentence using each of the two specifications is illustrated through an example.     

Relational Interpretations of Recursive Types in an Operational Setting

Relational interpretations of type systems are useful for establishing properties of programming languages. For languages with recursive types it is difficult to establish the existence of a relational interpretation. The usual approach is to pass to a domain-theoretic model of the language and, exploiting the structure of the model, to derive relational properties of it. We investigate the construction of relational interpretations of recursive types in a purely operational setting, drawing on recent ideas from domain theory and operational semantics as a guide. We prove syntactic minimal invariance for an extension of PCF with a recursive type, a syntactic analogue of the minimal invariance property used by Freyd and Pitts to characterize the domain interpretation of a recursive type. As Pitts has shown in the setting of domains, syntactic minimal invariance suffices to establish the existence of relational interpretations. We give two applications of this construction. First, we derive a notion of logical equivalence for expressions of the language that we show coincides with experimental equivalence and which, by virtue of its construction, validates useful induction and coinduction principles for reasoning about the recursive type. Second, we give a relational proof of correctness of the continuation-passing transformation, which is used in some compilers for functional languages.