Facebook carries out 4.5bn translations a day, all using machine learning

"Creating seamless, highly accurate translation experiences for the 2 billion people who use Facebook is difficult. We need to account for context, slang, typos, abbreviations, and intent simultaneously. To continue improving the quality of our translations, we recently switched from using phrase-based machine translation models to neural networks to power all of our backend translation systems, which account for more than 2,000 translation directions and 4.5 billion translations each day. These new models provide more accurate and fluent translations, improving people's experience consuming Facebook content that is not written in their preferred language."

Source:  Blog post on the Facebook code blog, 3rd August 2017

800m Facebook users use 'translate' each month

"Machine learning is accomplishing Facebook’s mission of connecting the world across language barriers. Facebook is now serving 2 billion text translations per day. Facebook can translate across 40 languages in 1,800 directions, like French to English. And 800 million users, almost half of all Facebook users, see translations each month.
That’s all based on Facebook’s own machine learning translation system. In 2011 it started working with Microsoft Bing to power translations, but has since bene working to transition to its own system. In December 2015, Facebook finally completed the shift, and now exclusively uses its own translation tech."

Source:  Techcrunch, 23rd May 2016