Dolphin Service Menu entry to OCR&PDF image files
tesseract must be installed on your system
Copy the .desktop file to $HOME/.local/share/kio/servicemenus/
Open Dolphin and go to Configure -> Configure Dolphin... (or press CTRL + SHIFT + ,)
Then go to the Context Menu section and click the button Download New Services... and search for OCR&PDF, then click Install
Go to the install path, open the .desktop file corresponding to this Service Menu entry with any text editor, and change the value of tesseract's -l argument from eng to the one of your liking (3-character ISO 639-2 code)