This tutorial shows how to change read more button titles.
Open the admin section, go to Extensions -> Language manager. Open the Overrides section, select the appropriate language and add a new Override.
You should search for Read more text. Make sure that the Value radio button is selected. Click More Results in order to see all results. Change the text and save the changes.
Add overrides for all Read more titles.
Refresh the page. We have changed Read more button titles.
Feel free to check the detailed video tutorial below:Joomla 3.x. How to change read more button titles,