Hi Metin,
Thanks for getting in touch and sorry for the trouble here with Turkish translations!
We did introduce a number of new language strings in The Events Calendar version 3.10 that were not available in version 3.9, so there will some words that have not been completely translated in the new version.
We do, however, have a new site dedicated to updating the calendar translations. If you check out the Turkish translation, it does appear that it is 90% complete, but still needs some strings translated to be completely finished.
You can update the .PO and .MO files you already have, or you can suggest new translations directly on the site, which we will approve and make available for download right there on the site as well. In fact, you an go ahead and download the most current language files from the site and work off of those, if you’d like. 🙂
Thanks again for reaching out and I hope this helps you get started for getting a more complete translation on your site. 🙂
Cheers!
Geoff