Translation of ownCloud is organized at Transifex.

Configure transifex

tx init

for resource in calendar contacts core files media gallery settings
do
tx set --auto-local -r owncloud.$resource "<lang>/$resource.po" --source-language=en \
 --source-file "templates/$resource.pot" --execute
done

Quick translation update:

cd l10n/ && perl l10n.pl read && tx push -s && tx pull -a && perl l10n.pl write && cd ..

The translation script requires Locale::PO, installable via apt-get install liblocale-po-perl

Make text translatable

1. In HTML or PHP wrap it like this <?php echo $l->t('This is some text');?>
   • For the right date format use <?php echo $l->l('date', time());?>. Change the way dates are shown by editing /core/l10n/l10n-[lang].php
   • To translate text in javascript use: t('appname','text to translate');
2. Add a folder l10n in the app. In there, have a file xgettextfiles and put in the paths to all files that have translatable texts (one per line, relative to the l10n folder)
3. Load all strings or update them: navigate to the main l10n folder and use the terminal command perl l10n.pl read
4. Send the updated sources to our translation platform Transifex: tx push -s

That’s it, now the translators can work. For more information, have a look at the inline documentation of lib/l10n.php