Comment 7 for bug 59765

depending on the package it appears in you go to that one and translate it in LP if you are a member of the specific l10n team. Depending on which plugin icons have bad labels
it could be xfce-mcs-plugins, xfwm4, xfce4-mixer etc, whichever package provides the plugin in /usr/lib/xfce4/mcs-plugins/
For dapper it could have happened that some user 'fixed' the translation in LP.
For edgy I am not sure if we are on upstream translations or a mix of that and LP translations. Unfortunately I cannot easily find the bug which I mentieoned earlier it was
closed after 6.06.1 released but I don;t remember it's subject or package, just that it was assigned to the ubuntu team and was marked 'major'.