Office suite by the Document Foundation. Forked from OpenOffice. Good accuracy for import/exporting Microsoft documents.

Either install an appropriate package from a link below, or use the GetLibreOffice tool:

LibreOffice 3.5.x and Language packs thread packaged by vicmz
Libreoffice-3.5.2.pet 151M, US language pack for Slacko

Also see the Slacko Repository for SFS and updates.

Many PET packages are available from the LibreOffice 3.5.x and Language packs thread.
Alternatively, get the language packs from the libre site. deb packages are easiest to install.

GetLibreOffice - Tool for installing LibreOffice with GUI
the Document Foundation
OpenOffice - suite by Apache
Ooo4Kids - cut down suite for children
OooLight - lightweight word-processor

LibreOffice homepage
LibreOffice 3.5.x and Language packs thread
GUI to download LibreOffice - beta quality thread
LibreOffice PET packages post