The Next/Prev buttons in the Carousel asset can be altered to show different wording.  You can do this by changing the wording in the XLIFF file for you course

The following steps detail how to do this;

1. From the Course Structure view select Translation Export (XLIFF) from the Actions dropdown list

2. This will download a zip file to your computer. The XLIFF zip will contain a number of files. Extract the localization-localization.xliff from the zip file and save locally

3. You can either use an XLIFF editor (there are some free Open Source ones available) or you can simply open it up in a text editor 

4. Use CTRL + F to search for the text: prev

6. Change the wording in the <target> field 

7. Change the wording for "next " using the same method

8. Save the changes to the file

9. Upload that file using the Translation Import (XLIFF) option 

10. The updated wording will display when you next preview the course