In US English, there is only one L in canceled, cancelation, etc.

#: ../calendar/calendar.error.xml.h:35
msgid ""
"If you don't send a cancellation notice, the other participants may not know "
"the journal has been deleted."

#: ../calendar/calendar.error.xml.h:36
msgid ""
"If you don't send a cancellation notice, the other participants may not know "
"the meeting is cancelled."

#: ../calendar/calendar.error.xml.h:37
msgid ""
"If you don't send a cancellation notice, the other participants may not know "
"the task has been deleted."

#: ../calendar/calendar.error.xml.h:55
msgid "Would you like to send a cancellation notice for this journal entry?"

#: ../calendar/calendar.error.xml.h:56
msgid "Would you like to send all the participants a cancellation notice?"

#: ../calendar/gui/e-itip-control.c:1230
msgid ""
"The meeting has been cancelled, however it could not be found in your "
"calendars"

#: ../calendar/gui/e-itip-control.c:1232
msgid ""
"The task has been cancelled, however it could not be found in your task lists"

(note that the last two strings are run-on sentences, and must both be changed. change the "however" to "but")

#: ../calendar/gui/e-itip-control.c:1348
#, c-format
msgid "<b>%s</b> has cancelled a meeting."

#: ../calendar/gui/e-itip-control.c:1349
msgid "Meeting Cancellation"

#: ../calendar/gui/e-itip-control.c:1425
#, c-format
msgid "<b>%s</b> has cancelled a task."

#: ../calendar/gui/e-itip-control.c:1426
msgid "Task Cancellation"

#: ../mail/mail-ops.c:761 ../mail/mail-send-recv.c:613
msgid "Cancelled."

#: ../mail/mail-send-recv.c:158
msgid "Cancelling..."

#: ../mail/mail-session.c:241
#, fuzzy
msgid "User cancelled operation."

#: ../plugins/itip-formatter/itip-formatter.c:805
#, c-format
msgid "Sent to calendar '%s' as cancelled"

#: ../plugins/itip-formatter/itip-formatter.c:905
msgid "Sent a cancellation notice to the delegate"

#: ../plugins/itip-formatter/itip-formatter.c:907                                                                               msgid "Could not send the cancellation notice to the delegate"

#: ../plugins/itip-formatter/itip-view.c:373
#, c-format
msgid "<b>%s</b> through %s has cancelled the following meeting:"

#: ../plugins/itip-formatter/itip-view.c:375
#, c-format
msgid "<b>%s</b> has cancelled the following meeting."

#: ../plugins/itip-formatter/itip-view.c:441
#, c-format
msgid "<b>%s</b> through %s has cancelled the following assigned task:"

#: ../plugins/itip-formatter/itip-view.c:443
#, c-format
msgid "<b>%s</b> has cancelled the following assigned task:"

#: ../addressbook/gui/widgets/eab-gui-util.c:61
#: ../calendar/gui/dialogs/task-details-page.glade.h:3
#: ../calendar/gui/e-cal-component-preview.c:234
#: ../calendar/gui/e-cal-model-tasks.c:349
#: ../calendar/gui/e-cal-model-tasks.c:662
#: ../calendar/gui/e-calendar-table.c:464 ../calendar/gui/print.c:2375
msgid "Cancelled"