Home page is created by “Theme Options” tab in Corpus Theme as you know. In order to translate Home Page (by using Polylang), it should be recognized by the plugin and related texts should be displayed under “String Translations” tab since it could not be re-developed by any other means. Other pages can be translated by creating separate pages but it is impossible for the home page since it is not recognized by Polylang plugin.
Our default language is Turkish and we need to translate this into English and Spanish. We thought that possibly Polylang is not compatible with Corpus theme and you may suggest another plugin.