I had to do this recently for a project of mine. There are 2 parts: 1) Breaking out all your text into language files, 2) Using the right language file.
1) Phalcon has built-in multi-language support, take a look at that.
2) How this is implemented depedns on your site. Often, I'll see urls like www.domain.com/en/some/page.html or www.domain.com/jp/some/page.html. The language to use can then be determined from the URL. If you have an existing site though, that may be difficult to implement. What I did for my site was have the user choose their language at log in. I then stored that language in their session, and accessed it every page load to determine what language to use. If you don't have a log in, you can set up your links similar to this: www.domain.com/language/choose/en/ and www.domain.com/language/choose/jp/. Then in your LanguageController
file, in the chooseAction()
method, you can simply set a session value.