Translation:The woman and the man have several elephants.
In Italian we have basically no difference between these terms. Are they somewhat interchangeable in Swedish as well, or do you use one for some things, and one for others?
Yes, "molto", "tanto", "parecchio" and "assai" are basically synonyms.
You use "flera" when you describe that someone has more than someone else; "Jag har fler syskon än dig". Meanwhile "många" is just a lot of something; "Jag har många syskon." you can also have "många fler...". Despite the fact that they have a little different mening I sometimes use "flera" instead of "många" ;)
Well, "it just does" I guess. It's a noun in the "third declination". Swedish nouns are divided into five groups called declinations:
First declination words end in -or in the plural (en flicka / flickor). Second declination in -ar (en hund / hundar), Third declination in -er (en elefant / elefanter) Fourth declination end in -n (ett äpple / äpplen) Fifth don't change in the plural (ett barn / barn)
There are some exceptions to the above, of course. When I first studied Swedish at school in the 90s, we just learned long lists of words by rote.