Datepicker in the right language

Is it possible to have the datepicker (of date field type) in the same language of the forms?
In a multilingual test website (localhost) with Polylang that manages the languages, as far as CF7 is concerned, it seems that I can have everything working and in the proper language (even the “choose file” button, if the language of the browser corresponds to the language selected) with the only exception of datepickers.
Whichever language I choose when I create a form the datepicker turns out to be always in english.
Thanks a lot

http://wordpress.org/plugins/contact-form-7/