How can I configure emails and invoices in other languages?

To enable email templates in additional languages, go to Configuration -> Email Templates ->  Click Configure Languages. Hover your cursor over the language you need and click Enable. 

 

To enable a different language for invoices: If you have enabled the Attach PDF option in the Invoice Settings, the attached PDF invoice will be translated into the same language as the email. For example, if the customer has selected Portuguese (Brazil), the invoice attachment will also be translated into Portuguese (Brazil).