A spaniard who doesn't speak catalan won't understand 95% of a normal convo... Catalan [0] is lexically as distant from the spanish as the Portuguese is [1]...
[0] https://en.wikipedia.org/wiki/Catalan_language
[1] https://elms.wordpress.com/2008/03/04/lexical-distance-among...
I don't know if I'd go that far. I just youtubed catalan and would say I understood about 75-80% of what this guy is saying. [1]
Also, I mainly meant that statement ironically :) Catalan is its own language, its just funny to me that "dialect" is a negative term, language is not, and usually the big country with the military dictates which provinces speak a "language" and which ones are speaking a "dialect".
[1] https://www.youtube.com/watch?v=wdiVss0X6V0&feature=youtu.be
Spanish speakers will notice a lot of "familiar words", but most of the time it's difficult for them to extrapolate the meaning of what is being said.
It’s like saying that german, dutch and english (Germanic languages) are extremely similar… =)
[1]https://youtu.be/2OynrY8JCDM?t=6m43s - interesting video overall
However the spoken form diverges much faster than the written form, to the point where it's completely impossible to have an oral conversation.
And Romanian, with only some more difficulty.
The big problems I see (as an Italian) when speaking with people from France, Spain, Portugal and Romania is mostly about the pronounciation, admittedly I have studied a little bit of French (that makes the "slightly more distant" language on par with the others).
When it is written, I can usually understand like 90% or more of most text and there are "sinergies", i.e. there is a given word that is different from Italian but is very similar to another word in another of the Latin languages or that is actually directly or almost directly a Latin word.
The issue is with "false pairs", i.e.words that exist (or sound alike or almost alike) in two languages but that have completely different meanings.
Like, to mention a couple reknown ones, "burro" which is "butter" in Italian and "donkey/ass" in Spanish or the Spanish "aceite" which most Italians will instinctively translate into "aceto" (vinegar) while it means "oil".
But in Europe I've been sitting on trains directly next to Portuguese speakers and had a very difficult time even understanding say 40% of what they were talking about. It was as if in Portugal they just chew up the words and chop them all up, which makes it super difficult to understand. That wasn't the case with the Brasilians I've spoken too. With them I could actually have conversations and know what they were saying.
But thats just my personal experience.
(I think. One of the characters in "Spotlight" was the most recent time I understood almost nothing.)
Try watching an English person ask an American (in the US) for water or where the herbs are.