The Japanese localization is a dead link: https://download.documentfoundation.org/libreoffice/stable/3.5.1/mac/x86/LibO_3.5.1_MacOS_x86_langpack_ja.dmg Not found.
Here the link: http://download.documentfoundation.org/libreoffice/stable/3.5.1/mac/x86/LibO_3.5.1_MacOS_x86_install_en-US.dmg
And the langpack link: http://download.documentfoundation.org/libreoffice/stable/3.5.1/mac/x86/LibO_3.5.1_MacOS_x86_langpack_ja.dmg