What is the difference between 'iso' and 'suuri'?
Could someone please explain to me the difference in usage between these? Thanks
They are almost interchangeable.
Almost, meaning that "iso" is always a reference to physical size (= big, large) while "suuri" can also have a figurative meaning (= great, grand)
So "iso mies" is a man who is physically big, while "suuri mies" can be a physically big man or someone accomplished and renowned (and prefix "suur-" is always figurative: suurmies, suurteko...)
And some idioms are specific: "hänellä on iso sydän" = he has a big blood-pumping muscle, "hänellä on suuri sydän" = he is a caring and compassionate person.
As mentioned, they can be used interchangeably, yet there is a slight difference when using it to describe something. "Suuri" is a bit bigger than "Iso".
In some cases, especially phrases, to a finn one just feels more correct than the other. Nothing to worry about at a beginnerlevel of finnish. Keep up the good work :)