You can completely remove a language and all its translations in the WPML Languages settings.
How can I remove a language and all its translations from my site?
To remove a language and all existing translations from your site:
Go to WPML → Languages.
Under Site Languages, click Add / Remove languages and unselect the language you want to remove. Click Save.
Editing languages in WPML
Once the page reloads, a table will appear. Click the X icon to delete all translations.
Deleting all language translations
WPML will now completely remove the language and all its translations from your website.
What can I do if my theme and plugins continue downloading language files in the removed language?
If your theme and plugins continue downloading language files in the removed language, you can delete all MO and PO files for that language:
Access your website using an FTP Tool such as FileZilla.
Go to your site’s ../wp-content/languages/plugins/ folder.
Delete the MO and PO files ending with the language code of the language you want to delete. For example, if you removed the Spanish language (ES) with the Spanish locale (es), the language files would end with -es_ES.mo and -es_ES.po.
To delete theme translations, open the themes folder in ../wp-content/languages/ and follow the instructions from the previous step.
