And what, please, is the difference between a "big" and a ,"large" language anyway? When is "suuri" used and when "iso"?? I wouldn't use these adjectives connected with a language anyway,
Niether is "large language" an English expression, I wonder where that comes from if it's not idiomatic in Finnish as well.
The phrase "suuri kieli" is not really used in Finnish although I do understand what is meant by this one. How about widely spoken = laajalti puhuttu?