賀江

【Abstract】With the development of modern transportation and communication means，the distance between people is becoming shorter and communication more frequent.Translation is playing an increasingly significant role in this process，and the traditional translation methods cannot meet the needs of modern society.The computer technology，the core of translation technique，serves as the supplementary role of human.The paper introduces the concept of “computer-aided translation”and its common types，analyzes its advantages and disadvantages，and then points out that only by combining machine translation with human translation can it produce sound translation works.

【Key words】machine translation； computer-aided translation； human translation

Now，with more and more frequent international communication，it has become a common requirement to quickly and accurately deal with foreign materials and computer-aided translation （referred to by the abbreviation CAT） may help to solve the issue.

1.The definition of machine translation and CAT

Machine translation，sometimes referred to by the abbreviation MT，is a sub-field of computational linguistics that investigates the use of software to translate text or speech from one natural language to another.On a basic level，MT performs simple substitution of words in one natural language for words in another.

CAT，at a valuable development stage of MT，is a form of language translation in which a human translator uses computer software to support and facilitate the translation process.Though imperfectly developed，CAT，has a strong storage capacity and uses its fast searching ability to assist translation.And CAT incorporates the manual editing stage into the software，making translation an interactive process between human and computer.

2.The history and current situation of CAT in China

The idea of MT may be traced back to the 17th century.In 1629，René Descartes，a French scientist，proposed a universal language，with equivalent ideas in different tongues sharing one symbol.Then Warren Weaver，an American scientist，mathematician and science administrator，wrote an important memorandum “Translation”in 1949.And the idea of using digital computers for translation of natural languages was proposed as early as 1946 by A.D.Booth，an English engineer.The Georgetown experiment was by no means the first of such application，and a demonstration of a rudimentary translation of English into French was made in 1954 on the APEXC machine at Birkbeck College （University of London）.A similar application，also pioneered at Birkbeck College at the time，was reading and composing Braille texts by computer.And Warren Weaver and A.D.Booth first put forward the idea of using the computer to produce automatic translation.All these meant that MT had entered a new stage.Beginning in the late 1980s，as computational power increased and the computer became less expensive，more interest was shown in statistical models for MT.Various MT companies were launched，including Trados （1984），which was the first to develop and market translation memory technology （1989）.At this time，MT has been at its peak and the development of the theory of computational linguistics has also gradually been improved.

China has paid high attention to MT research.Especially from the early 1990s to the present，MT has seen rapid development in theory and practice.In 1995，translation research center of the University of Manchester Institute of Science & Technology created the corpus of English and since then many countries have built a lot of large parallel corpus.In 2000，China began to establish its own corpus.For instance，the National Research Centre of Beijing Foreign Studies University established the “general Chinese-English parallel corpus” and the state key laboratories of intelligent technology of Tsinghua University jointly developed the bilingual parallel corpus.

3.The main forms of CAT

The translation tools of CAT include terminology management，translation memory systems，retrieval tools and so on.The function of terminology management system lies in rectifying and standardizing the terminology to ensure the standardization and accuracy of translation.Translation memory，the key technology of the current mainstream of CAT software，can store the translated database of the original text and the translated version.The following are the main forms of CAT.

1）Corpus aided translation.The functions of corpus aided translation mainly lie in selecting suitable translation version，searching and standardizing words of human translation.Another function is to enrich the existing traditional grammar and dictionary，which contributes to accumulating a huge mass of bilingual corpora.Whats more，it is capable of memorizing and storing the previously translated sentence fragments，phrases and the whole text，which，to a large extent，simplifies and improves the efficiency.

2）Electronic dictionaries and network translation.The traditional dictionary tends to be more limited in vocabulary and it causes inconvenience to daily use for it cannot timely collect new words.However，electronic dictionaries installing computer technology has large capacity and function fast.Network translation also shares the same advantages.Via these tools，people can look up words，quickly browse the network and have the access to relevant data.

3）The electronic reference book and telephone translation.The electronic reference book has powerful information retrieval ability.And it is worth attention that natural voice has been conducted to operate CAT.For instance， recently，Microsoft's Skype Translator，a new app，has been designed to translate ones speech in real time，making it possible to hold a conversation in a language you dont understand.

4.The advantages of CAT

With traditional translation methods，the translator has to refer to dictionaries and reference books repeatedly and write the translation on the paper word for word，which is time-consuming and mechanical.However，avoiding the mentioned repeated labor，CAT enjoys the following advantages：

1）It increases efficiency of translation.When time is a crucial factor，CAT can save the day.There is no need to spend hours poring over dictionaries to translate the words.Instead，the software can translate the content quickly and provide a quality output to the user in no time at all.

2）It provides extensive vocabulary and information for translation.As CAT is a large dictionary，it spares translators referring to the dictionary.And CAT is capable of applying professional knowledge to grammar and vocabulary and finally forming the discourse.

CAT provides as much the information as possible.Rich data not only can improve the efficiency，they can also increase the accuracy and consistency.Now there are many translation software including the dictionary and thesaurus containing a large amount of information.Whats more，CAT usually translates the text which is in any language so there is no such concern when a professional translator specializes in one particular field.

5.The disadvantages of CAT and its improvement strategies

Though CAT provides more sound and more convenient working environment for the translation，it still has its own disadvantages.

1）Accuracy is not offered by CAT on a consistent basis.One can get the gist of the draft or documents without comprehending the information which might have to be corrected manually later on.

2）Systematic and formal rules are followed by CAT so it cannot concentrate on a context and solve ambiguity and neither makes use of experience or mental outlook as a human translator can.

3）The current development of the translation software is still not soundly perfect as the translation software are mainly developed by computer scholars while translation is the activity of human language，so some settings of CAT still need improving.

In the coming research and development of CAT，it needs the cooperation of experts in computer，translation，linguists and mathematics.Only by joint effort can some better translation software be created.In addition，there is still a long way to enhance translators skill in operating the computer to be the interdisciplinary talents.

From the above analysis，it is not hard to see that CAT has its own features and it is believed that with the progress of science and technology，there will be more developed technologies to serve the translation work.