For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/X11:common:Factory/openSUSE_Tumbleweed/X11:common:Factory.repo
zypper refresh
zypper install translation-update
For openSUSE Factory ARM run the following as root:
zypper addrepo https://download.opensuse.org/repositories/X11:common:Factory/openSUSE_Factory_ARM/X11:common:Factory.repo
zypper refresh
zypper install translation-update
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/X11:common:Factory/15.5/X11:common:Factory.repo
zypper refresh
zypper install translation-update