Cohesion and coherence in the presentation of machine translation products
Muriel Vasconcellos · 1989
Different degrees of human intervention can be applied to the preparation of machine translation (MT) products in readying them for their ultimate use. It is suggested here that differences in levels of postediting are associated to some extent with cohesion and coherence. The posteditor is essentially an interpreter of discourse: much of the postediting task involves either employing devices to ensure that the surface pieces of the discourse are connected in meaningful ways or else adjusting the reading of each item against the interpretation of others until the entire underlying text is made to cohere. The presence of cohesion and coherence is examined in three versions of the same machine translation: the raw output, a lightly postedited version, and the final, fully postedited product. 1. Perspective on MT postediting. Machine translation can be delivered the end user as raw output, of course, and it can also be postedited to varying degrees. There is much to be learned from a look at the doctoring that is done when the machine stops working and the human user takes over. Certainly a linguistic study of intervention in the MT product at different levels of refinement can help us to prioritize our strategies. By stratifying the types of corrections that are made, we can begin to orient postediting policy so that today's MT systems are used more effectively, and we can also contribute to the improved performance of the systems of tomorrow. 1 In practice, time and cost constraints often lead to situations in which postediting is curtailed to one degree or another. Depending on the purpose of the translation, nuancing may be traded off for expediency and economy, The most drastic curtailment, of course, is no postediting at all, as is sometimes the policy with translations for information only. Usually, however, even with informative translations there is some type of human intervention. Newman (1988), based on experiments with the SYSTRAN and LOGOS MT systems, has recommended limiting information-only postediting to the replacement of foreign words—words not found in the MT dictionary. Somewhat more intervention is practiced at the U.S. Air Force Foreign Technology Division, where 'partial postediting' addresses seven types of target errors (Bostad 1987). SYSTRAN's Russian-English translations are passed through an automatic postprocessor (EDITSYS) which produces warning flags; whenever any of the seven types of error occurs in the output, the human operator is alerted by a flashing line across the screen. The corrections elicited by EDITSYS will affect, on average, about 20% of the output (Bostad 1987:438). As with most 'information-only' translation, the material handled by the Air Force covers a broad range of subjects and comes