Twitter today announced that it has opened up its Translation Center to crowd-source translations of right-to-left languages, allowing users to read tweets in a specialised interface and use hashtags in languages including Arabic, Farsi, Hebrew and Urdu.

Asking for volunteers via its official blog, Twitter hopes that its users will step forward to join the 425,000 existing contributors to its Translation Center, which have already helped to make Twitter available in 22 languages.

We spoke with Twitter’s Director of Platform Ryan Sarver and UK General Manager Tony Wang in December 2011, where the company was preparing to roll out the new version of its website and mobile applications.

Wang said at the time:

“I often get asked how big do you think Twitter is going to be. The answer to that is, well, how many people are there in the world?”

By opening its platform to encompass Arabic, Farsi, Hebrew and Urdu languages, Twitter is truly working towards making its service available to the 7 billion people on earth.

The company has already developed “new ways to ensure that Tweets and hashtags will work properly in right-to-left languages,” adding that it had also “made changes behind the scenes to give right-to-left language speakers a localized user experience.”

That means that as soon as the translators have done their thing, the company will make the new languages available to everyone on Twitter.com by the Spring.