In addition to having evolved, for the most part, separately from one another and with distinct individual histories, the Latin-based regional Romance languages of Italy are also better classified as separate languages rather than true "dialects" due to the often high degree in which they lack mutual intelligibility. Though mostly mutually unintelligible, the exact degree to which the regional Italian languages are mutual unintelligible varies, often correlating with geographical distance or geographical barriers between the languages, with some regional Italian languages that are closer in geographical proximity to each other or closer to each other on the dialect continuum being more or less mutually intelligible. For instance, a speaker of purely Eastern Lombard, a language in Northern Italy's Lombardy region that includes the Bergamasque dialect, would have severely limited mutual intelligibility with a purely standard Italian speaker and would be nearly completely unintelligible to a speaker of a pure Sicilian language variant. Due to Eastern Lombard's status as a Gallo-Italic language, an Eastern Lombard speaker may, in fact, have more mutual intelligibility with a Occitan, Catalan, or French speaker than a standard Italian or Sicilian language speaker. Meanwhile, a Sicilian language speaker would have an greater degree of mutual intelligibility with a speaker of the more closely related Neapolitan language, but far less mutual intelligibility with a person speaking Sicilian Gallo-Italic, a language that developed in isolated Lombard emigrant communities on the same island as the Sicilian language.

What is a major reason why the Latin-based regional Romance languages of Italy should be regarded as independent languages rather than dialects of each other?