The social web is increasingly multilingual. About half the updates on Twitter are in a language other than English, according to a study released in February. Facebook has been translated into more than 50 languages for its 500 million users are all over the world. The day when English is no longer the dominant language on social networks may not be far off.

Social Translate is a new open source extension for Google’s Chrome browser that translates updates on social networking sites into your native language using Google Translate.

You can choose between “reliable,” which appears to attempt fewer translations, or “aggressive,” which is less accurate but attempts to guess at more words.

Of course, Google Translate’s ability is limited, and it seems to extract less meaning when the sentences are short.

A tweet from one of the top users in Beijing translated from Chinese to English using Social Translate.

Social Translate is a useful and relevant idea for a web that is increasingly composed of conversations. The extension has some shortcomings and a few bugs, judging by a quick test and its page on Google Code.

It detects languages correctly on Twitter and translates acceptably (except for the fact that Google Translate often turns up total nonsense), letting users skip the Google Translate prompt that appears when you navigate to a site in a foreign language. If your first language is English but you’re also fluent in Spanish, you can tell Social Translate to display Spanish tweets but translate any other language to English.

On Facebook, the extension is measurably less useful. It only translates status updates as they appear in your News Feed – not in comments on updates, in profiles or on users’ walls.

It appears the two developers, Andrew Swerdlow and Nav Jagpal, are still working out the kinks with this extension. I could not get the extension to work for MySpace or Google Buzz, although the developers intend for it to work for those services.

Update: Just got an email from Swerdlow, who says they are testing a build that works with Buzz and hope to ramp up on some of the other big sites over the next few months. If you download Social Translate, you can test it by going to Swerdlow’s multilingual Twitter page,