Google Translate marked its sixth birthday on Thursday with news that more than 200 million people use the free online translation service monthly.

"In a given day we translate roughly as much text as you'd find in one million books," Google Translate engineer Franz Och said in a blog post.

"We imagine a future where anyone in the world can consume and share any information, no matter what language it's in, and no matter where it pops up."

Och worked at US military research arm DARPA before joining California-based Google in 2003 to be part of a team of engineers ramping up the quality of computer-driven language translations.

Google Translate, which lets people paste or type text in an on-screen box to have it quickly converted into a language of their choice, rolled out in 2006 with English, Chinese and Arabic.

"We can now translate among any of 64 different languages, including many with a small Web presence, such as Bengali, Basque, Swahili, Yiddish... and even Esperanto," Och said of the service at translate.google.com.

Traffic to Translate from smartphones has been growing exponentially, and more than 92 percent of the users are from outside the United States, according to Google.

"What all the professional human translators in the world produce in a year, our system translates in roughly a single day," Och said.

"By this estimate, most of the translation on the planet is now done by Google Translate."