Neapolitan is a Romance language spoken by about seven or eight million people in southern Italy, especially in the city of Naples (Nàpule/Napoli) and in Campania and southern Lazio. Neapolitan is part of a continuum of dialects spoken in most of southern Italy, though many would only use the term 'Neapolitan' only to refer to the dialects spoken in and around Naples.
Neapolitan developed from Vulgar Latin, like most of the other languages and dialects spoken in Italy, and also contains some influences from Oscan and Greek.
Today Neapolitan is used mainly as a spoken language, though it has been used in literature since the 15th century. It has no official status and is not used in education, but is often used in popular songs.
source
wikipedia.org,
omniglot.com &
ethnologue.com