My understanding is that The Silmarilion was originally conceived as wrapped in Bilbo's Translations ftom the Elvish*. Christopher Tolkien said that he regrette

My understanding is that The Silmarilion was originally conceived as wrapped in Bilbo's Translations ftom the Elvish*. Christopher Tolkien said that he regretted not having that in the published version. But there was never any talk of a new edition.