Italian is one of the world’s ancient and most-spoken languages, with nearly 100 million speakers in the world today. According to Wikipedia, nearly 16% of the population of Europe speaks Italian as a first or second language, and it is spoken in Italy, Switzerland, San Marino, Vatican City, Malta, Slovenia, Croatia, France, Libya, Monaco, Somalia, Montenegro, and Eritrea as a first or second language. There are also other parts of the world where Italian immigrants have settled and the language is still spoken, including the United States.
The Italian language comes from ancient Latin mostly, and unlike most other derivatives of Latin still retains many words that are distinctly and recognizably Latin. Of all the languages descended from Latin, Italian is touted as the one most similar to Latin today. Some languages, even a few other widely-spoken languages, are similar to Italian, such as Spanish and Portuguese, and have many interchangeable words and phrases.
There are many Italian dialects, since almost every city in Italy has a distinct dialect that is unique to that area. Different major cities adapted Italian into their own cultures, producing a few dialects vastly different than others, such as Milanese Italian versus Roman Italian. As Italian people began emigrating, these dialects were adopted and mingled with other languages as well, and the version of Italian spoken somewhere such as France or the United States is different than the Italian spoken in Vatican City, for example.