Approaches To Machine Translation

The aim of machine translation (MT) is to produce high-quality translation automatically. Though this aim is not yet achieved MT research has achieved significant developments. This article intends to explain the design strategies for machine translation. Bilingual MT systems are designed specifically for particular two languages, Tamil and English, for example. Multilingual MT systems support translation of more than two languages. There are three basic approaches as listed below.

1. Direct Translation
2. Interlingua Approach
3. Transfer Approach

Direct translation approach belongs to the first generation of machine translation systems. The interlingua and transfer approaches are characteristic of the second generation systems.

1. Direct Translation

Direct translation is also called binary translation approach as it is designed for a particular pair of languages. Translation is direct from the source text to the target text. Very little syntactic and semantic analysis are done. Source language analysis is oriented specifically to the production of equivalent target language text. MT systems that use this approach use a bilingual dictionary.

2. Interlingua Approach

An interlingua is a knowledge representation formalism

. It is language neutral as it is independent of the way particular languages express meaning. Interlingual machine translation techniques produce the interlingua in such a way that translating from source language to more than one target language is possible. Interlingua approach has to face the challenge of designing an efficient and comprehensive knowledge representation. Moreover complete resolution of all ambiguities in the source language text is required to make this approach possible.

3. Transfer Approach

Transfer approach has three stages. The first stage converts source language text into abstract source language oriented representations. The second stage deals with lexical differences between languages and converts the representations resulted from the first stage into corresponding target language representations. Finally the third stage generates the target language text. Transfer systems require dictionaries for source and target languages. These dictionaries should contain morphological, grammatical, and semantic information. A bilingual transfer dictionary is required to relate base source language forms and base target language forms.

Both interlingua and transfer approaches are now known generically as rule-based systems.