Hey Christina,
Apologies for the delayed response, we normally try to issue a reply once every twenty-four hours at least.
You asked this in your reply:
Does that mean if I purchase the plug in it would only work with our English site but not for the sites in other languages?
• If you have WPML active on your site, our plugin will not work with it. This does not matter whether you have only one language, English or otherwise, or if you have many languages on the site. If WPML is active, then calendar features may break.
• If you do NOT have WPML activated on your site at all, then you can use The Events Calendar and any add-ons for it without issue.
• Our plugins DO support being translated into one language, so you can use our plugins in English, OR Spanish, OR French, etc.—you just cannot use WPML to try and pull off having the calendar in English AND Spanish for example.
I hope this clarification of some things helps! Let me know! 😀
— George