Noptin is fully compatible with the latest version of Polylang allowing you to run a multilingual newsletter.
Translate Forms
You can translate your newsletter subscription forms into each of your site’s languages.
To do this:-
Click on Noptin Newsletter > Subscription Forms to open the subscription forms overview page…

… then click on the + sign to translate the form into a new language or the pencil icon to edit an existing translation.

That’s all.
Every time you display a subscription form on your website, Noptin will try to display the translated version whenever possible. Learn more about translating custom content with Polylang.
Translate Settings
To display confirmation messages and send double opt-in emails in the subscriber’s language, you have to first translate the plugin settings.
To do this:-
Click on Languages > String Translations to open the string translations section…

… then use the “group filter” at the top of the page to search for Noptin settings.

Finally, translate each string into each language that you support.