In both these folders:
phpBB/language/en/email/
phpBB/language/en/email/short/

There are some files that are almost identical called:
bookmark.txt
newtopic_notify.txt
post_approved.txt
post_disapproved.txt
post_in_queue.txt
privmsg_notify.txt
quote.txt
report_pm.txt
report_post.txt
topic_approved.txt
topic_disapproved.txt
topic_in_queue.txt
topic_notify.txt

Should the /short/ folder be deleted?
Or how come the same files exists twice?
It would be a bit easier for translators if each file only exists once.

There is two difference in these two files, so someone might want to look at what would be best to keep:
phpBB/language/en/email/topic_notify.txt
phpBB/language/en/email/short/topic_notify.txt
:

since your last visit. No more notifications will be sent until you visit the topic.

since your last visit. You can use the following link to view the replies made, no more notifications will be sent until you visit the topic.

{U_STOP_WATCHING_TOPIC}

{U_STOP_WATCHING_TOPIC}