You are the funniest person I know.
Correct
The blue whale is the biggest animal in the world.
Correct
This book is the most interesting one I read this year.
Correct
My sister is intelligenter than my brother.
Wrong
The cheetah is the most fastest animal.
Wrong.
The Nile is the longest river in the world.
Correct
Anna is the youngest person in the classroom.
Correct
Norway is coldest than Spain.
Wrong.
Today is the hottest day of the year.
Correct
I'm gooder at English than you.
Wrong
Sarah is shorter than me.
Correct
The giraffe is more tall than the elephant.
Wrong
Zootopia is the most funny than Vivo.
Wrong
This is the most bad song I have ever listened.
Wrong
This exam is difficulter than the last one.
Wrong
The city is the beautifuler one in the world.
Wrong
English is more easier than Japanese.
Wrong
Gonzalo is the most dirty than Jorge.
Wrong