The Neapolitan dialects are distributed throughout most of continental southern Italy, historically united during the Kingdom of Naples and the Kingdom of the Two Sicilies, specifically southern Lazio (Gaeta and Sora districts), southern Marche, Abruzzo, Molise, Basilicata, Campania (Naples), northern and central Apulia, and northernmost Calabria. The dialects are part of a varied dialect continuum, so the varieties in southern Lazio, Marche, Abruzzo, Molise, Apulia, Lucania and Calabria can typically be recognizable as regional groups of dialects. In western Abruzzo and Lazio the dialects give way to Central Italian dialects such as Romanesco. In central Calabria and southern Apulia, the dialects give way to the Sicilian language. Largely due to massive southern Italian migration in the late 19th century and early 20th century, there are also numbers of speakers in Italian diaspora communities in the United States, Canada, Australia, Brazil, Argentina and Venezuela. However, in the United States traditional Neapolitan has had considerable contact with English, and is significantly different from contemporary Neapolitan spoken in Naples. English words are often used in place of Neapolitan words, especially among second-generation speakers. On the other hand, the effect on Neapolitan in Italy has been similar due to displacement by Standard Italian.
The following dialects constitute Neapolitan; numbers refer to the map:
- Abruzzese and Southern Marchigiano:
- Ia. Southern Marchigiano (Ascoli Piceno).
- Ib. Teramano (province of Teramo; northern province of Pescara: Atri, Abruzzo).
- Ic. Abruzzese Eastern Adriatico (Southern province of Pescara: Penne, Francavilla al Mare; province of Chieti).
- Id. Western Abruzzese (southern part of province of L'Aquila: Marsica, Avezzano, Pescina, Sulmona, Pescasseroli, Roccaraso).
- Molisan (Molise)
- Apulian (Pugliese):
- IIIa. Dauno (western province of Foggia: Foggia, Bovino).
- IIIb. Garganico (eastern province of Foggia: Gargano).
- IIIc. Barese (province of Bari; western province of Taranto (includes Tarantino dialect); and part of the western province of Brindisi).
- Campanian (Campania),
- IVa. Southern Laziale (southern part of province of Frosinone: Sora, Lazio, Cassino; southern part of Province of Latina: Gaeta, Formia).
- IVb. Naples dialect (Neapolitan proper: Naples and the Gulf of Naples).
- IVc. Irpino (province of Avellino).
- IVd. Cilentano (southern part of province of Salerno: Vallo della Lucania).
- Lucanian and Northern Calabrian:
- Va. Northwestern Lucanian (northern province of Potenza: Potenza, Melfi).
- Vb. Northeastern Lucanian (province of Matera: Matera).
- Vc. Central Lucanian (province of Potenza: Lagonegro, Pisticci, Laurenzana).
- Vd. Southern Lucanian. The "Lausberg Area"; archaic forms of Lucanian with Sardinian vocalism (described in Lausberg 1939). It lies between Calabria and Basilicata (Chiaromonte, Oriolo).
- Ve. Cosentino (province of Cosenza: Rossano, Diamante, Castrovillari). With transitional dialects to south of Cosenza, where they give way to Sicilian group dialects.
The southernmost regions of Italy—most of Calabria and southern Apulia, as well as Sicily—are home to Sicilian rather than Neapolitan.