Update internationalization labels for new and missing labels

[autumnfound]

In the time that we've received initial translations of content for i18n labels, some new ones have been added in the meantime. We should investigate what labels are missing from the list for which language and ask for assistance from the community in updating these values.

[autumnfound]

This replaces #83 to be more all-encompassing for i18n issues.

[ericpoirier]

@autumnfound can you provide links of the pages where labels should be updated?

Thanks.