Just look at the "Community Activity" section in the Main Page. The log entries indicate things like: "about 1 hour ago". As the "ago" part of the message is set for translation, for example, in Galician it appears "hai about 1 hour" instead of "hai aproximadamente 1 hora".
TWN has chosen not to translate those parts of the code that are already translated through the Rails i18n system itself; this is one of those messages. I suspect that support for Galician may be weak on that project. If you're motivated to do so, you could help via the git codebase directly: https://github.com/svenfuchs/rails-i18n