All translators advertise themselves as quality translators, so how do you which one will produce a quality job? It is better to have no website than a mistranslated website. The mistranslated website will unfortunately turn off potential clients. An expertly translated website the flows smoothly in the new language as though it was written in it original makes the client more likely to identify the product, and thus more likely to buy.
What should you look for on the website of a translation firm that is most likely to give you a quality translation?
Here are what translators in the field say:
The US Government Translation Bureau:
Competence in two languages is necessary but not sufficient for any translation task. Though the translator must be able to (1) read and comprehend the source language and (2) write comprehensibly in the target language, the translator must also be able to (3) choose the equivalent expression in the target language that both fully conveys and best matches the meaning intended in the source language.It then goes on to say that a weakness in any of these three criteria will reduce the quality of translation. Something to look out for.
They say the highest level of translation, a professional will be able to:
capture subtleties, nuances, and tone and register (such as official, formal, and informal writing). Such texts range from commentary reflecting a specific culture to analysis and argumentation
Gabe Bokor of http://translationjournal.blogspot.com says:
Translator buyers therefore use translators' credentials to predict their performance. These credentials may include:
a college degree in translation
a college degree in the subject-matter field
a professional certification
a sample translation (not necessarily in the field in question)
client references
professional experience in a non-linguistic field
Which of these (or other) credentials are the best predictors of a translator's performance? Which ones can be faked, lied about, or dismissed as irrelevant?
Another way is to go to local professional certification. For Ontario, Canada, for example, it is the following: ATIO, Association of Translators and Interpreters of Ontario.
http://www.atio.on.ca/info/AdvertPage.asp
If you are not sure of the quality or it is the first time contacting a translation firm, ask them to do a sample of two lines from the document that requires translation. Then ask someone who is a native speaker of the language those lines are translated into if it sounds right.
Always pick human translation over machine translation. Machine translation like on google can be free, but usually causes embarrassing errors due to lack of nuance. For example a label on a Turkish shirt that is supposed to say "Made in Turkey" instead reads "Fabriqué en Dinde". It means literally made in a turkey, as in the bird, instead of made in Turkey, the country. Hundreds of these shirts are printed. Do you think the buyer would believe "Haute Qualité. Fabriqué en Dinde"? [Roughly = High quality, made inside a turkey]. Unlikely. Human translation picks up on subtleties that can make or break the presentation of your product.
Good luck!

