TRANSLATION AS A MULTISTAGE TRANSFORMATION

FI­GURE IV.13. The role of dictionaries and grammars in linguistic transformations.

The task of translation from one natural language to another is a good illustration of multistage transformation of linguistic information.

Suppose there is a text in a language A that is to be translated into language B. As we have already argued, word-by-word translation leads to very poor and useless results. To translate the text with highest possible quality, the following stages of transformation are necessary:

· First stage of analysis starts from the source text in the language A and gives its morphologic representation specific for language A.

· Second stage of analysis starts from the morphologic representation and gives the syntactic representation specific for language A.

· Third stage of analysis starts from the syntactic representation and gives some level of semantic representation. The latter can be somewhat specific to language A, i.e., not universal, so that additional intra-level operations of “universalization” of semantic representation may be necessary.

The problem is that currently it is still not possible to reach the true semantic representation, i.e., the true level of Meaning, consisting of the universal and thus standard set of semes. Therefore, all practical systems have to stop this series of transformations at some level, as deep as possible, but not yet at that of universal Meaning.

· The transfer stage replaces the labels, i.e., of the conventional names of the concepts in language A, to the corresponding labels of language B. The result is the corresponding quasi-semantic level of representation in language B. In some cases, additional, more complex intra-level operations of “localization” are necessary at this stage.

· First stage of synthesis starts from the quasi-semantic representation with few features specific for the language B, and gives the syntactic representation quite specific for this language.

· Second stage of synthesis starts from the syntactic representation, and gives the morphologic representation specific for language B.

· Third stage of synthesis starts from the morphologic representation, and gives the target text in language B.

In the initial stages, the transformations go to the deep levels of the language, and then, in the last stages, return to the surface, with the ultimate result in textual form once more. The deeper the level reached, the smaller the difference between the representations of this level in both languages A and B. At the level of Meaning, there is no difference at all (except maybe for the labels at semes). The deeper the level reached during the transformations, the smaller the differences that have to be ignored, and the better the quality of translation (see Figure IV.14). This scheme shows only the general idea of all these representations.

FIGURE IV.14. Translation as multistage transformation.

The given scheme works for an arbitrary pair of natural languages. However, if the two languages are very similar in their structure, the deeper stages of the transformation might not be necessary.

For example, if we translate from Spanish into Portuguese, then, because these two languages differ mainly in their lexicon, it can be sufficient to use only the first stage of analysis and the last stage of synthesis, just replacing each Spanish word by the corresponding Portuguese one on the morphologic level.

In Figure IV.14 this would correspond then to the “horizontal” transition directly on this level.