Quote Originally Posted by Gigliozzi
News flash, people: Italian and Spanish are NOT OH MY GOD OH SO SIMILAR!!! They just sound like it, but there are huge difference just like with any two languages. If you claim you understand Italian because you already speak Spanish and viceversa, I'm sorry to have to put it this way, but you're talking out of your ass. Just be real.

In fact, in my experience, I have found far more cognates between French and Italian than between Spanish and Italian. That being said, I'm not going to go around and claim I understand French, because I don't.
It's true. Italian is more closely related to French than any of the other major Romance languages (although it could be argued that grammatically it has a lot more in common with Romanian). My ability to read Italian is not entirely based on my knowledge of French and Spanish however.

I am a big language geek, and I love studying the history of languages. The division of Latin into the Romance languages is one of the best documented cases of dialects splitting up into their own languages, and I have spent a lot of time studying how that happened. In the process I have learned a lot of Latin roots and am familiar with most of the sound changes that turned ancient Latin into modern Italian (and modern French, Spanish, Portuguese, etc.).

With a good enough understanding of how Latin developed differently in the different regions of the former Roman Empire, it becomes simple to recognize cognates that don't superficially resemble each other, like Spanish "hoja" and Italian "foglia" ('leaf', related to the English word "foliage" through Latin), or French "journée" and Italian "giorno" ('day', related to the English word "diurnal" through Latin). Using such connections, and studying basic Italian grammar, I have trained myself to understand pretty much every word in an Italian text with little effort.

Italian and Spanish are very similar, certainly more similar than English is to its closest cousin Dutch. Italian is a lot more like Spanish and French than, say, Greek or Russian or English, because it is much more closely related to those languages than to the others. Of course there are lots of differences (that's why we call them separate languages), but compared to other languages there's no question that Italian and Spanish have a lot in common.