Hi, @berkant
Thanks for reaching out in our Community forums and for sharing your concern, I’d be happy to help.
I can understand the urgency of this issue. There are a few causes that lead to this error related to your theme code or translation app. My first suggestion would be to head over to your language editor within the Shopify Admin. This can be accessed by clicking on Online Store > Themes > Actions > Edit Languages. From there, you should be able to see the notice for the missing translation. You can simply fill the words back in and then this error should be resolved.
Let me know if this helps! If you do not see the banner, feel free to provide some additional information regarding your theme and how you are translating your site.
Talk soon!