Different types of systems
There are different types of systems that are used in machine translation. In general, systems are intended either for two specific languages (so-called bilingual systems) or for more than two languages (so-called multilingual systems). As to bilingual systems, they can be developed in order to function in only single direction (so –called unidirectional systems), for instance from Polish into English, or in both directions (bidirectional systems). It should be mentioned that multilingual systems are typically designed to be bidirectional and the majority of bilingual systems are unidirectional.
As far as a general system design is concerned, there are three rudimentary types of machine translation. The first type is usually termed as the direct translation approach in which the MT system is designed specifically for single particular pair of languages, for example Polish as the language of the source texts and English as the language of the target texts. In this system, translation is direct from the source language to the target language and the rudimentary supposition is that the vocabulary and syntax of SL does not need be analysed to greater extent than necessary for the clearance of uncertainties. Characteristically, these systems comprise an enormous bilingual dictionary and a single monolithic program that is used in order to analyse and generate texts. For that reason, direct translation systems are unavoidably bilingual and unidirectional.
As to the second rudimentary design, it is the interlingual approach in which it is assumed that it is possible to transform source language texts into depictions that are common to more than single language. It is from these interlingual representations from which texts are produced into other languages. Therefore, it can be seen that in situations in which interlingua approach is employed, translation is conducted in two stages: from SL to the interlingua (IL) and from the IL to the TL. In addition, procedures for source language analysis are meant to be source language-specific and not focused on any specific target language. Similarly, programs for target language synthesis are target language-specific and not developed for input from specific source languages.