change language

How can I change the language of the feed burner popup ?

Feedburner gives this info:

For the subscription form:
Add the following “hidden” element somewhere between the opening <form> and closing </form> tags:

<input type="hidden" name="loc" value="es_ES"/>

For the subscription link:
Add the following parameter to the end of address shown in the “href” attribute of the “a” tag:

<a href="https://www.feedburner.com/fb/a/emailverifySubmit?feedId=25&loc=es_ES">...

Thanks.