There are two ways to delete your account in the BNR Language apps:
Using the app, go to the "Settings / Account" screen, then select the "Delete Account" option and follow the on-screen instructions to confirm the deletion of your account and all stored data;
Send an email to bnrlanguages@gmail.com requesting the deletion of your account and all stored data.
Once the account is deleted, all stored data will be permanently erased.