Vulgar Latin had, no doubt, its own local peculiarities before the fall of the Empire. The political instability that followed Roman rule kept Italy from re-uniting as a nation until the nineteenth century. This long period of fragmentation and the fact that Classical Latin was preferred as the international language of study allowed the various modes of speech to develop on their own until they could almost be called separate languages.
Many dialects are, in fact, unintelligible with each other.
With the political reunification of the peninsula and the degree of travel and relocation that began to take place, the need for a national language became all the more urgent. This need was met by the literary language, which had evolved as a standardized form of Florentine. Today, thanks to aggressive education programs, the literary language is used throughout the country for law, business, and education. The dialects are finding themselves relegated to home use, or between close neighbors in urban neighborhoods and villages. There are two major groups of Italian dialects, excepting the Sardinian group which is considered another language entirely.