How to change reCAPTCHA language on websites?
It depends on what is your version reCAPTCHA.
In version 2, you just need to specify the parameter ?hl= in the script's URL:
<script src='https://www.google.com/recaptcha/api.js?hl=fr'></script>
In version 3, you just need to specify the parameter ?lang= in the script's URL:
https://www.google.com/recaptcha/api.js?render=reCAPTCHA_site_key&lang=en
Change language in reCaptcha url explicitly,
https://www.google.com/recaptcha/api.js?explicit&hl=fa'> for Persian or https://www.google.com/recaptcha/api.js?explicit&hl=en'> for English or any other language