Internationalization
You don't have to create an extra file, you only have to register all message keys with SRF_Messages.php and publish those keys with SRF_Resources.php as well (see example 'messages' => array( ...)) to ensure the resource file is able to access those messages. (If you register message keys with SRF_Resources.php than the ResourceLoader integration will taken care of.)
The only thing that is left is to adjust the ext.srf.eventcalendar.js file with those message keys (using mw.msg( 'srf-eventcalendar-label-...' )) so the fullcalendar object can access those translated messages. (see links above for proposed methods on how this can be achieved in a fullcalendar instance ).
If you need advise on how to add translations to SMW/SRF messages files (SRF_Messages.php), you can contact Kghbln on this matter.
Please be remind that all what is provided here is community work and since my timetable will not allow me to drill into this further, I hope the above description is enough to give you a heads up otherwise you might consult [1], [2] as well.
[1] http://www.mediawiki.org/wiki/ResourceLoader/Features
[2] https://www.mediawiki.org/wiki/Localisation#Using_messages_in_JavaScript
Well, since I figured that might take a bit for you to get it work. I added i18n support with [1]. Which means as soon as the keys are available in translatewiki, you can start to translate
'srf-ui-eventcalendar-label-today' => 'Today',
'srf-ui-eventcalendar-label-month' => 'Month',
'srf-ui-eventcalendar-label-week' => 'Week',
'srf-ui-eventcalendar-label-day' => 'Day',
'srf-ui-eventcalendar-label-allday' => 'All day',
'srf-ui-eventcalendar-format-time' => 'h(:mm)t',
'srf-ui-eventcalendar-format-time-agenda' => 'H:mm( - H:mm)',
'srf-ui-eventcalendar-format-axis' => 'H:mm',
'srf-ui-eventcalendar-format-title-month' => 'MMMM yyyy',
'srf-ui-eventcalendar-format-title-week' => 'd [ yyyy]{ \'—\'[ MMM] d MMM yyyy}',
'srf-ui-eventcalendar-format-title-day' => 'dddd, d MMM, yyyy',
'srf-ui-eventcalendar-format-column-month' => 'ddd',
'srf-ui-eventcalendar-format-column-week' => 'ddd d/M',
'srf-ui-eventcalendar-format-column-day' => 'dddd d/M',
Month, days are taken from MW's own message key's, so no need for any translation.
