This problem is caused when another facebook script on your website is overriding the language settings of our facebook live chat.
Example: //connect.facebook.net/en_US/sdk.js (on your website) should be //connect.facebook.net/pl_PL/sdk.js (or your language)
(en_US = English) (pl_PL = Ex. your language)
You may need a developer to help you update the scripts on your website. We can not do this on our end.