Language is partly science, but mostly art, and although programming algorithms and artificial intelligence have undergone amazing developments in the last several decades, no one has yet developed an online translator that can produce eloquent, grammatically correct prose. And although I suspect most readers of this blog are well aware of this fact, I shall now demonstrate my point with a real example.
Here is a randomly-chosen fragment of an article from the Spanish newspaper El Pais:
China e India han acordado, tras años de negociaciones, reabrir al comercio, el próximo 6 de julio, el paso fronterizo de Nathu, que se convertirá de esta forma en el primero abierto a intercambios económicos entre ambos países desde la guerra que mantuvieron en 1962, según ha informado la agencia Xinhua.
This is my translation:
After years of negotiations, China and India have agreed to reopen commerce. On July 6, the border pass of Nathu will be opened, thus creating the first opportunity for economic exchange between the two countries since the 1962 war, according to the Xinhua news agency.
Now, here is a sampling of results from three online translators:
China and India has decided, after years of negotiations, to reopen to commerce, next 6 into July, step border of Nathu, which it will become of this opened form first to economic interchanges between both countries from the war which they maintained in 1962, according to has informed Xinhua agency.
Chinese and India they have agreed, after years of negotiations, to reopen al commerce, the next one 6 of July, the border crossing of Nathu in which will be converted in this way in the first open one to economic exchanges among both countries since the war that maintained in 1962, has reported the agency Xinhua.
China and India have decided, after years of negotiations, to reopen to the commerce, next the 6 of July, the border step of Nathu, that one will become of this opened form first to economic interchanges between both countries from the war that maintained in 1962, according to Xinhua agency has informed.
Sure, it's comprehensible. But is it good English? No. And this example was relatively straightforward, whereas longer excerpts are likely to contain convoluted grammar, advanced vocabulary, or idioms that can't be translated literally. Online translators simply can't handle these.
So what's a person to do? If you're trying to read a foreign-language website, then the online translations might well be sufficient, and I can't deny that they're free and easy to obtain. But if you're translating anything into a foreign language and you care at all about the results, there is as yet no substitute for a human---I dare to add, even a human who isn't completely fluent in that language. If quality is of paramount importance, hire a professional translator. If not, there are numerous ways to find native speakers, particularly for common languages, and in my experience, many people are happy to do translations for free. But unless you're willing to have your foreign reader think of you the same way you think of someone who writes like Babelfish, skip the online translators.