Tallest is the superlative.
smallest is the superlative. (est is the standard superlative ending._
bigger is the comparativebiggest is the superlative
The superlative of clear is clearest.
Fattest is the superlative of fatter.
The superlative of grateful is most grateful.
grateful.* more grateful.* most grateful.
More generous and most generous
The comparative form of "grateful" is "more grateful".
Grateful
I'll be forever grateful and I am grateful mean the same thing. Both saying are sad when someone is grateful for something.
Grateful
i am not grateful to you.
There can be many sentences using grateful. One such is, I am grateful to have a friend like you.
"Grateful" in Sanskrit can be written as "कृतज्ञ" which is transliterated as "Kṛtajña".
Sleep is a noun and does not have a superlative. Sleepy is an adjective and the superlative is "sleepiest."
The superlative for willing would be "most willing." There is no one-word superlative.