Apple's latest upgrade of iWork finally has the full set of 18 OS X localizations. Previous versions only had 8. Aside from that, however, I was not able to find any improvements in language capabilities. In particular, longstanding bugs in input/editing of RTL scripts like Arabic and Hebew have not been fixed. The ability to use Windows Arabic fonts, introduced in TextEdit with OS X 10.5, is still absent in these apps. Options for vertical layout and ruby annotation which Japanese/Chinese language users want have not been added. And the strange Unicode input bugs described here remain.
The new iWork requires 10.5.6 or 10.4.11.