Data is not deleted from database with cache clean up.
Somebody deleted languages in your cart.
First try select
select * from ac_languages;
Note: ac_ might be different on your database. This depends on the prefix you used to install.
If there is nothing returned in SQL, this will prove that someone deleted languages.
To restore:
Locate file install/abantecart_database.sql
If you deleted, get it from Git:
https://github.com/abantecart/abantecart-src/tree/master/public_html/installLook for tables ac_languages and ac_language_definitions
You need to run DROP, CREATE and INSERT SQLs for these tables.
Clear cache and you can confirm languages in admin of storefront.