Hello Márcio

I am sorry to disappoint you, but unfortunately something like this is not possible with the plugin's built-in features.

Our developers are currently working on an integration with multi-lingual plugins, so I hope it will become available soon. At the moment, I can only offer a workaround - an add-on for Polylang - Theme and plugin translation for Polylang (TTfP). One of our customers used it, and managed to translate email notifications, custom fields and extras with it.

I'm not sure how that add-on works, Márcio.

The customer that mentioned this didn't go into depth about how it is used. She did say that she couldn't translate buttons and placeholders for Stripe Payment, but that's as much info as I have.

I don't have Polylang, so I was unable to test this. I'd like to take a look, though, so please provide me a temporary WP-admin login for your site where this happens, so we could log in and take a look ‘from the inside’ as that’s the most efficient way to see and resolve the issue. We do not interfere with any data or anything else except for the plugin (in case that’s a production version of the site), and of course we do not provide login data to third party. 

You can write credentials here just check Private Reply so nobody can see them except us.