Post-Editing Machine Translation

Statistical Machine Translation (SMT) has many uses – from the translation of User Generated Content (UGC) to Technical Documents, to Manuals and Digital Content. While some use cases may only need a ‘gist’ translation without post-editing, others will need a light to full human post-edit, depending on the usage scenario and the funding available.

Post-editing is the process of ‘fixing’ Machine Translation output to bring it closer to a human translation standard. This, of course is a very different process than carrying out a full human translation from scratch and that’s why it’s important that you give full training for staff who will carry out this task.

Training will make sure that post-editors fully understand what is expected of them when asked to complete one of the many post-editing type tasks. Research (Vasconcellos – 1986a:145) suggests that post-editing is a honed skill which takes time to develop, so remember your translators may need some time to reach their greatest post-editing productivity levels. KantanMT works with many companies who are post-editing at a rate over 7,000 words per day, compared to an average of 2,000 per day for full human translation.

Types of Training: The Translation Automation User Society (TAUS) is now holding online training courses for post-editors.

post-editing

Post-editing Levels

Post-editing quality levels vary greatly and will depend largely by the client or end-user. It’s important to get an exact understanding of user expectations and manage these expectations throughout the project.

Typically, users of Machine Translation will ask for one of the following types of post-editing:

  • Light post-editing
  • Full post-editing

The following diagram gives a general outline of what is involved in both light and full post-editing. Remember however, the effort to meet certain levels of quality will be determined by the output quality your engine is able to produce

post-editing machine translation

Generally, MT users would carry out productivity tests before they begin a project. This determines the effectiveness of MT for the language pair, in a particular domain and their post-editors ability to edit the output with a high level of productivity. Productivity tests will help you determine the potential Return on Investment of MT and the turnaround time for projects. It is also a good idea to carry out productivity tests periodically to understand how your MT engine is developing and improving. (Source: TAUS)

You might also develop a tailored approach to suit your company’s needs, however the above diagram offers some nice guidelines to start with. Please note that a well-trained MT engine can produce near human translations and a light touch up might be all that is required. It’s important to examine the quality of the output with post-editors before setting productivity goals and post-editing quality levels.

PEX Automatic Post-editing

Post-Editor Skills

In recent years, post-editing skills have become much more of an asset and sometimes a requirement for translators working in the language industry. Machine Translation has grown considerably in popularity and the demand for post-editing services has grown in line with this. TechNavio predicted that the market for Machine Translation will grow at a compound annual growth rate (CAGR) of 18.05% until 2016, and the report attributes a large part of this rise to “the rapidly increasing content volume”.

While the task of post-editing is markedly different to human translation, the skill set needed is almost on par.

According to Johnson and Whitelock (1987), post-editors should be:

  • Expert in the subject area, the text type and the contrastive language.
  • Have a perfect command of the target language

Is it also widely accepted that post-editors who have a favourable perception of Machine Translation perform better at post-editing tasks than those who do not look favourably on MT.

How to improve Machine Translation output quality

Pre-editing

Pre-editing is the process of adjusting text before it has been Machine Translated. This includes fixing spelling errors, formatting the document correctly and tagging text elements that must not be translated. Using a pre-processing tool like KantanMT’s GENTRY can save a lot of time by automating the correction of repetitive errors throughout the source text.

More pre-editing Steps:

Writing Clear and Concise Sentences: Shorter unambiguous segments (sentences) are processed much more effectively by MT engines. Also, when pre-editing or writing for MT, make sure that each sentence is grammatically complete (begins with a capital letter, has at least one main clause, and has an ending punctuation).

Using the Active Voice: MT engines work impressively on text that is clear and unambiguous, that’s why using the active voice, which cuts out vagueness and ambiguity can result in much better MT output.

There are many pre-editing steps you can carry out to produce better MT output. Also, keep in mind writing styles when developing content for Machine Translation to cut the amount of pre-editing required. Get tips on writing for MT here.

For more information about any of KantanMT’s post-editing automation tools, please contact: Gina Lawlor, Customer Relationship Manager (ginal@kantanmt.com).

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