The frenchified formation"more correct" is preferred, but the native English formation "correcter" is not incorrect. It does have lower status, though, and is considered unsuitable for writing. School-marms will keep "correcting" it until you become an accomplished author and then it will be a robust element of your style.
The comparative degree of "correct" is "more correct."
more correct
better for its comparative and best for its superlative
The comparative degree of the adverb "sadly" is "more sadly."
The comparative degree form of "pitiful" is "more pitiful."
comparative degree: more truthful superlative degree: most truthful
lusher
More correct
Neither. Pretty is the positive degree. The comparative is prettier; the superlative is prettiest.
Teapot is a noun and, as such, does not have a comparative degree.
"Less" is the comparative degree of little.
The comparative degree is bigger.
The comparative degree is wider.
More wicked Most wicked
Thriftier is the comparative degree of thrifty.
"Speed" is a noun and a verb and, as such, does not have a comparative degree. The comparative of the adjective speedy is speedier.
"Less" is the comparative degree of little. The superlative degree is least.
"Message" is a noun and (these days) a verb and, as such, does not have a comparative degree.
The comparative degree of "sad" is "sadder."