A [https://nap.wikipedia.org/wiki/Chiàcchiera:Paggena_prencepale#Sostituire_nnapulitano_con_napulitano request (in Italian)] has been made on the Neapolitan Wikipedia (nap.wikipedia.org) to change the name of the language "nap" from "Nnapulitano" to "Napulitano".
The reasoning is (basically) as follows:
- The doubling of the letter "n" at the beginning of the word is the effect of the neuter article "'o"
- Since there is no article before the word, the consonant should not be doubled
You should of course read the request for more details. The user claims to be a native speaker of the Neapolitan language.
This is identical to [http://unicode.org/cldr/trac/ticket/5544].