Is Italian the modern form of Latin or is it a spin-off language similar to Spanish?

Answer 1

In one sense, yes. Italian is the result of the development of the language of Italy from ancient Rome to the present. There has been a change from one to the other over the course of millenia, from classical Latin to late Latin to medieval Latin to "vulgar" Latin to old Italian to modern Italian.

However, since so much time has passed and "Italian" has become so different from what we recognize as "Latin", they are better classified as two different languages. You can't speak modern Italian if all you've learned is medieval Latin, and vice versa. You probably wouldn't be able to carry a conversation with one person speaking Italian and the other Latin, so they're not dialects, either.

A good comparison would be between modern English (American or British, it doesn't matter) and Old English. Note that I don't mean the archaic, Elizabethan-era English used by Shakespeare. I mean the Old English of Beowulf, so different from our English that it didn't even use the Roman alphabet. There is no way an English-speaker today would be able to follow a conversation or read a book in Old English without deliberate study. There may be some apparent similarities — one is a development of the other, after all — but they are not interchangeable as the "same" language.

With regard to other Romance languages like Spanish, Italian is in a similar yet different position. All the Romance languages are direct descendants of Latin, with varying degrees of influence from other local languages. But Italian could be considered the most direct descendant, on account of having developed in the home and birthplace of the Latin language.