Happy Birthday, ICU!

The ICU project is celebrating 10 years of being open source this month.

"ICU" in this case stands for International Components for Unicode - not to be confused with Intensive Care Unit or International Communist Union... It is the premier software internationalization library, appearing in everything from your Google Android phone or your iPod all the way up to IBM mainframes. It provides the Unicode support that all of these programs need for handling the languages of the world, from Arabic to Chinese to Vietnamese.

ICU originated back in an Apple/IBM/HP joint venture. That code was morphed into the core of Java internationalization for JDK 1.1.4 - a large portion of this code still exists in the java.text and java.util packages. At that time, it included pretty much just sorting, locale/message support, and formatting for dates, numbers and so on. (If you're interested in early history, see an older paper by Laura Werner - now at Google). The libraries were refined over time and ported back to C and C++; now there are also wrappers for other languages, such as PHP.

ICU's data comes from the Unicode Consortium's open source project for locale data - CLDR - and typically releases each new version right after CLDR does. CLDR 1.7 was just released Friday, May 8, with ICU 4.2 following on the very same day.

While ICU was around before Google, more recently Google has played a strong role in the development of ICU, and in providing major contributions to the Unicode CLDR project. ICU forms the foundation of our 40 language initiative, so we look forward to many successful future birthdays!


By Mark Davis, Internationalization team