Facebook Widget Preview language depends on - Logged In "Admin" Location. :) If you are from Netherlands or any Dutch speaking countries, Facebook will show you text in like box in Dutch.
But i'll fix it next time. I'll give an option, so Site Admin will be able to choose the language :)
Thank you for bringing this issue.
Sorry, this caused you trouble :( I fixed this and updated the plugin, this caused due to - new like box preview option.
Please do rate our plugin in wordpress.org :) https://wordpress.org/support/plugin/cardoza-facebook-like-box/reviews/ :)