Hello!
How is your site structured? Do you have languages on different subdomains (e.g. en.yoursite.com / es.yoursite.com), folders (yoursite.com/en), some other way (yoursite.com/mainpage?lang=en)? The first one will allow you to split your link sources in a more efficient way.
However, in general, link should be obtained from a related source. So if some page on your site is in spanish, it is obvious you want to be linked from a spanish page, which content is related to your topic.
