When dealing with payment forms in multiple languages, you can easily make mistakes.
Like forgetting to change everything in all languages.
To keep yourself sane, I recommend that you use just one form (for all languages) by creating your own dictionary (Settings-Language), see my previous post.
In order to send receipts by email in the selected language, you will have to add a hidden field in the form (you can name the field anyway you like):
Then, in the Form-Send to-Email you can add one email for each language and use a rule to select what email is to be sent.
Email 2:
The rule:
Now, you can use the same form for all languages!