Nobody in Sicily drops the vowels at the end of words, and I'm there all the time, around them all the time. Dropping vowels at the end of words is the way Italian-Americans speak when they think they're speaking Sicilian, but actually have no idea what they're saying.
And today, all the new generations are brought up speaking Italian proper.
Actually they're imitating, or sometimes speaking the Neapolitan dialect.
Even 100 years ago people learned to speak/read/write actual Italian in southern Italy if they were educated, or had intelligence.
Where did they learn to speak/read/write Italian proper? Who taught them? They spoke what their families were speaking in the house. Dialect. They barely made it thru elementary school, so no...they weren't being taught proper because many left school very early on and it wasn't necessary to learn Italian like it is today. Don't mistake being ignorant for being stupid, though.
They learned it in school where it was taught. My friends and relatives who are very older some of who are no longer alive said how they just learned actual Italian. I know that one relative of mine learned Italian in school, and learned more of it because his parents wanted him to become a priest but instead of doing that he went to the United States after being sponsored by his brother. The older Calabrians I know who are in their early 80s said how they did not learn dialect and just learned how to speak/read/write Italian, and how most people did not go beyond what we would call late elementary school or early jr. highschool.
The Sicilians I know who are older in their 60s and 70s said how they would speak dialect at home; but at school they wrote/read/spoke actual Italian. They were in parochial schools though, so maybe that has something to do with it?
But these people did not stay in Italy some moved when they were 10, 16, or when they were married and in their 20s.
