The topic of MT is one that we have found sufficiently interesting to spend most of our professional lives investigating, and we hope the reader will come to share, or at least understand, this interest. But whatever one may think about its intrinsic interest, it is undoubtedly an important topic --- socially, politically, commercially, scientifically, and intellectually or philosophically --- and one whose importance is likely to increase as the 20th Century ends, and the 21st begins.
The social or political importance of MT arises from the socio-political importance of translation in communities where more than one language is generally spoken. Here the only viable alternative to rather widespread use of translation is the adoption of a single common `lingua franca', which (despite what one might first think) is not a particularly attractive alternative, because it involves the dominance of the chosen language, to the disadvantage of speakers of the other languages, and raises the prospect of the other languages becoming second-class, and ultimately disappearing. Since the loss of a language often involves the disappearance of a distinctive culture, and a way of thinking, this is a loss that should matter to everyone. So translation is necessary for communication --- for ordinary human interaction, and for gathering the information one needs to play a full part in society. Being allowed to express yourself in your own language, and to receive information that directly affects you in the same medium, seems to be an important, if often violated, right. And it is one that depends on the availability of translation. The problem is that the demand for translation in the modern world far outstrips any possible supply. Part of the problem is that there are too few human translators, and that there is a limit on how far their productivity can be increased without automation. In short, it seems as though automation of translation is a social and political necessity for modern societies which do not wish to impose a common language on their members.
This is a point that is often missed by people who live in communities where one language is dominant, and who speak the dominant language. Speakers of English in places like Britain, and the Northern USA are examples. However, even they rapidly come to appreciate it when they visit an area where English is not dominant (for example, Welsh speaking areas of Britain, parts of the USA where the majority language is Spanish, not to mention most other countries in the world). For countries like Canada and Switzerland, and organizations like the European Community and the UN, for whom multilingualism is both a basic principle and a fact of every day life, the point is obvious.
The commercial importance of MT is a result of related
factors. First, translation itself is commercially important: faced
with a choice between a product with an instruction manual in English,
and one whose manual is written in Japanese, most English speakers
will buy the former --- and in the case of a repair manual for a piece
of manufacturing machinery or the manual for a safety critical system,
this is not just a matter of taste. Secondly, translation is expensive.
Translation is a highly skilled job, requiring much more than mere
knowledge of a number of languages, and in some countries at least,
translators' salaries are comparable to other highly trained
professionals. Moreover, delays in translation are costly. Estimates
vary, but producing high quality translations of difficult material, a
professional translator may average no more than about 4-6 pages of
translation (perhaps 2000 words) per day, and it is quite easy for
delays in translating product documentation to erode the market lead
time of a new product. It has been estimated that some 40-45% of the
running costs of European Community institutions are `language costs',
of which translation and interpreting are the main element. This would
give a cost of something like million per
annum. This figure relates to translations actually
done, and is a tiny fraction of the cost that would be involved in
doing all the translations that could, or should be done.
Scientifically, MT is interesting, because it is an obvious application and testing ground for many ideas in Computer Science, Artificial Intelligence, and Linguistics, and some of the most important developments in these fields have begun in MT. To illustrate this: the origins of Prolog , the first widely available logic programming language, which formed a key part of the Japanese `Fifth Generation' programme of research in the late 1980s, can be found in the `Q-Systems' language, originally developed for MT.
Philosophically, MT is interesting, because it represents an attempt to automate an activity that can require the full range of human knowledge --- that is, for any piece of human knowledge, it is possible to think of a context where the knowledge is required. For example, getting the correct translation of negatively charged electrons and protons into French depends on knowing that protons are positively charged, so the interpretation cannot be something like ``negatively charged electrons and negatively charged protons''. In this sense, the extent to which one can automate translation is an indication of the extent to which one can automate `thinking'.
Despite this, very few people, even those who are involved in producing or commissioning translations, have much idea of what is involved in MT today, either at the practical level of what it means to have and use an MT system, or at the level of what is technically feasible, and what is science fiction. In the whole of the UK there are perhaps five companies who use MT for making commercial translations on a day-to-day basis. In continental Europe, where the need for commercial translation is for historical reasons greater, the number is larger, but it still represents an extremely small proportion of the overall translation effort that is actually undertaken. In Japan, where there is an enormous need for translation of Japanese into English, MT is just beginning to become established on a commercial scale, and some familiarity with MT is becoming a standard part of the training of a professional translator.
Of course, theorists, developers, and sellers of MT systems must be mainly responsible for this level of ignorance and lack of uptake, and we hope this book will help here --- one motivation for writing this book was our belief that an understanding of MT is an essential part of the equipment of a professional translator, and the knowledge that no other book provided this in accessible form.
We are reminded of this scale of ignorance every time we admit to working in the field of MT. After initial explanations of what MT is, the typical reaction is one of two contradictory responses (sometimes one gets both together). One is ``But that's impossible --- no machine could ever translate Shakespeare.'' The other is ``Yes, I saw one of those in the Duty Free Shop when I went on holiday last summer.'' These reactions are based on a number of misconceptions that are worth exposing. We will look at these, as well as some correct conceptions, in the next section.